isr lab manual fina

INFORMATION STORAGE AND RETRIEVAL LAB

1.Write a C++ program to read series of names, one per line, from standard input and write these names spelled in reverse order to the standard output using I/O redirection and pipes. Repeat the exercise using an input file specified by the user instead of the standard input and using an output file specified by the user instead of the standard output

#include<iostream.h>#include<fstream.h>#include<string.h>#include<stdlib.h>

// function to read names from standard input and display reverse of same names on standard output //

void standard_io(){

cout<<"\n Enter the number of names \n"; int n; cin>>n; cout<<"\n Enter the names \n"; char name[10][20]; int i; char *temp1;

for(i=0;i<n;i++){

cin>>name[i];temp1=(char *)malloc(sizeof(name[i]));temp1=strrev(name[i]);cout<<"\n"<<temp1;

}}

// function to read the names , write them into a user defined file and then write the reverse of names into another user defined file //

void userfile_io(){

cout<<"\n Enter the name of the file into which names have to be stored \n";char ifilename[10];cin>>ifilename;cout<<"\n Enter the name of the file into which the names will have to be written in reverse order \

n";char revfilename[20];cin>>revfilename;cout<<"\n Enter the number of names \n";int n;cin>>n;cout<<"\n Enter the name \n";char name[10][10];

Department of ISE, SIT, Tumkur - 1 -


char *temp1;ofstream out(ifilename);int i;for(i=0;i<n;i++){

cin>>name[i];out<<name[i]<<endl;

}out.close();ifstream in(ifilename);char temp[10];out.open(revfilename,ios::out);while(in>>temp!=NULL){

temp1=(char *)malloc(sizeof(temp));temp1=strrev(temp);out<<temp1<<endl;

}in.close();out.close();}

// main function begins //

int main(){

int ch; do{

cout<<"\n 1-Standara input/output \n 2-User specified file input/output \n 3-Exit \n Enter your choice \n";

cin>>ch;if(ch==1)

standard_io();else if(ch==2)

userfile_io();}while(ch<3);return 0;

}

// main function ends //

OR



#include<fstream.h>#include<iostream.h>#include<string.h>#include<conio.h>

int main(){ char name[10][20]; char temp[20]; char ifilename[15], ofilename[15]; int num; int i=0; cout<<"Enter how many person details you want to enter: "; cin>>num; cout<<"Enter the file name where it has to be written: "; cin>>ofilename;

ofstream ofileobj(ofilename,ios::out); cout<<"Enter person details: "; while(i<num) { cin>>name[i]; ofileobj<<name[i]<<endl; i++; } ofileobj.close(); cout<<"Enter the file name where output has to be written: \n ";

cin>>ifilename; ifstream inobj(ofilename,ios::in); ofileobj.open(ifilename,ios::out);

cout<<"The details of the person in reverse that are entered is:\n"; while(inobj >> temp != NULL) { cout<<strrev(temp)<<endl; ofileobj<<temp<<endl; } getch(); return 0;}

2. Write a C++ program to read and write student objects with fixed-length records and the fields delimited by “|”. Implement pack ( ), unpack ( ), modify ( ) and search ( ) methods



#include<stdio.h>#include<stdlib.h>#include<iostream.h>#include<fstream.h>#include<conio.h>#include<string.h>#include<iomanip.h>

class student{ public: char name[15],usn[15],age[5],sem[5],branch[15],buffer[45];};

student s2[100];

void writeRecord() //Function to add record to file{ fstream app; student s; app.open("student.txt",ios::app); //Open file in append mode

if(!app) { cout<<"cannot open the file in output mode"; getch(); exit(0); } cout<<"\n Enter the student name = "; cin>>s.name; cout<<"\n Enter the usn = "; cin>>s.usn; cout<<"\n Enter the age = "; cin>>s.age; cout<<"\n Enter the sem = "; cin>>s.sem; cout<<"\n Enter the branch = "; cin>>s.branch;

//packing the information strcpy(s.buffer, s.name); strcat(s.buffer,"|"); strcat(s.buffer, s.usn); strcat(s.buffer,"|"); strcat(s.buffer, s.age); strcat(s.buffer,"|"); strcat(s.buffer, s.sem); strcat(s.buffer,"|"); strcat(s.buffer, s.branch);

int count=strlen(s.buffer); for(int k=0;k<45-count;k++) strcat(s.buffer,"!"); strcat(s.buffer,"\n"); app<<s.buffer; //writing the packed information to buffer app.close();}

void search()



{ fstream in; char usn[15], extra[45]; in.open("student.txt",ios::in); if(!in) { cout<<"\nUnable to open the file in input mode"; getch(); exit(0); } cout<<"\nEnter the record's usn you want to search = "; cin>>usn; student s;

//Unpacking the record while(!in.eof()) { in.getline(s.name,15,'|'); in.getline(s.usn,15,'|'); in.getline(s.age,5,'|'); in.getline(s.sem,5,'|'); in.getline(s.branch,15,'|'); in.getline(extra,45,'\n');

if(strcmp(s.usn,usn)==0) {

cout<<"\nRecord found";cout<<"\n"<<s.name<<"\t"<<s.usn<<"\t"<<s.age<<"\t"<<s.sem<<"\t"<<s.branch;getch();return;

} } cout<<"\n Record not found"; getch(); return;}

void displayFile(){ student s; int c,i; char extra[45]; fstream in; in.open("student.txt",ios::in);

if(!in) { cout<<"\nCannot open the file in output mode"; getch(); exit(0); } i=0; printf("Name\t\tUsn\t\tAge\t\tSem\t\tBranch\n");



while(!in.eof()) { in.getline(s.name,15,'|'); in.getline(s.usn,15,'|'); in.getline(s.age,5,'|'); in.getline(s.sem,5,'|'); in.getline(s.branch,15,'!'); in.getline(extra,45,'\n'); printf("\n%s\t\t%s\t\t%s\t\t%s\t\t%s",s.name,s.usn,s.age,s.sem,s.branch);

i++; } in.close(); getch();}

void modify(){ fstream in; char usn[15],buffer[45],extra[45]; int i,j; student s1[100]; in.open("student.txt",ios::in); if(!in) { cout<<"\nUnable to open the file in input mode"; getch(); exit(0); } cout<<"\nEnter the usn"; cin>>usn; i=0;//Loading the file to Main memory while(!in.eof()) { in.getline(s1[i].name,15,'|'); in.getline(s1[i].usn,15,'|'); in.getline(s1[i].age,5,'|'); in.getline(s1[i].sem,5,'|'); in.getline(s1[i]. branch, 15,'\n'); in.getline(extra,45,'\n'); i++; } i--; for(j=0;j<i;j++) { if(strcmp(usn,s1[j].usn)==0) {

cout<<"\nThe old values of the record with usn "<<usn<<" are ";cout<<"\nname = "<< s1[j].name;cout<<"\nusn = "<< s1[j].usn;cout<<"\nage = "<< s1[j].age;cout<<"\nsem = "<< s1[j].sem;



cout<<"\nbranch = "<< s1[j].branch;

cout<<"\nEnter the new values \n";cout<<"\nname = "; cin>>s1[j].name;cout<<"\nusn = "; cin>>s1[j].usn;cout<<"\nage = "; cin>>s1[j].age;cout<<"\nsem = "; cin>>s1[j].sem;cout<<"\nbranch= "; cin>>s1[j].branch;break;

} } if(j==i) { cout<<"\n Record with usn "<<usn<<" is not present"; getch(); return; } in.close(); fstream out1; out1.open("student.txt",ios::out); if(!out1) { cout<<"\nUnable to open file in output mode"; getch(); return; } for(j=0;j<i;j++) { strcpy(buffer,s1[j].name); strcat(buffer,"|"); strcat(buffer,s1[j].usn); strcat(buffer,"|"); strcat(buffer,s1[j].age); strcat(buffer,"|"); strcat(buffer,s1[j].sem); strcat(buffer,"|"); strcat(buffer,s1[j].branch);

int count=strlen(buffer); for(int k=0;k<45-count;k++) strcat(buffer,"!");

strcat(buffer,"\n"); out1<<buffer; } out1.close();}

void main(){ fstream in; fstream out; int ch; out.open("student.txt",ios::out); if(!in) {



cout<<"\n\nCannot open the file in output mode"; getch(); exit(0); } out.close();

for(;;) { clrscr(); cout<<"\n O:exit\n 1: write to file\n 2:display the file"

<<"\n 3:modify the file\n 4:search"; cout<<"\n\n Enter the choice: "; cin>>ch; switch(ch) { case 1: writeRecord();break; case 2: displayFile();break; case 3: modify();break; case 4: search (); break; case 0: exit(0); default: cout<<"\nInvalid input....";break; } }}

3. Write a C++ program to read and write student objects with Variable - Length records using any suitable record structure. Implement pack ( ), unpack ( ), modify ( ) and search ( ) methods.



#include<stdio.h>#include<stdlib.h>#include<iostream.h>#include<fstream.h>#include<conio.h>#include<string.h>#include<iomanip.h>

class student{ public: char name[15],usn[15],age[5],sem[5],branch[15],buffer[100];};

student s2[100];

void writeRecord(){ fstream app; student s; app.open("student.txt",ios::app); //Open file in append mode

if(!app) { cout<<"cannot open the file in output mode"; getch(); exit(0); } cout<<"\n Enter the student name = "; cin>>s.name; cout<<"\n Enter the usn = "; cin>>s.usn; cout<<"\n Enter the age = "; cin>>s.age; cout<<"\n Enter the sem = "; cin>>s.sem; cout<<"\n Enter the branch = "; cin>>s.branch;

//packing the information strcpy(s.buffer, s.name); strcat(s.buffer,"|"); strcat(s.buffer, s.usn); strcat(s.buffer,"|"); strcat(s.buffer, s.age); strcat(s.buffer,"|"); strcat(s.buffer, s.sem); strcat(s.buffer,"|"); strcat(s.buffer, s.branch);strcat(s.buffer,"\n");

app<<s.buffer; //writing the packed information to buffer app.close();}

void search(){ fstream in; char usn[15], extra[45]; in.open("student.txt",ios::in); if(!in)



{ cout<<"\nUnable to open the file in input mode"; getch(); exit(0); } cout<<"\nEnter the record's usn you want to search = "; cin>>usn; student s;

//Unpacking the record while(!in.eof()) { in.getline(s.name,15,'|'); in.getline(s.usn,15,'|'); in.getline(s.age,5,'|'); in.getline(s.sem,5,'|'); in.getline(s.branch,15,'\n');

if(strcmp(s.usn,usn)==0) {

cout<<"\nRecord found";cout<<"\n"<<s.name<<"\t"<<s.usn<<"\t"<<s.age<<"\t"<<s.sem<<"\t"<<s.branch;getch();return;

} } cout<<"\n Record not found"; getch(); return;}

void displayFile(){ student s; int c,i; fstream in; in.open("student.txt",ios::in);

if(!in) { cout<<"\nCannot open the file in output mode"; getch(); exit(0); } i=0; printf("Name\t\tUsn\t\tAge\t\tSem\t\tBranch\n"); while(!in.eof()) { in.getline(s.name,15,'|'); in.getline(s.usn,15,'|'); in.getline(s.age,5,'|');



in.getline(s.sem,5,'|'); in.getline(s.branch,15,'!'); printf("\n%s\t\t%s\t\t%s\t\t%s\t\t%s",s.name,s.usn,s.age,s.sem,s.branch); i++; } in.close(); getch();}

void modify(){ fstream in; char usn[15],buffer[45],extra[45]; int i,j; student s1[100]; in.open("student.txt",ios::in); if(!in) { cout<<"\nUnable to open the file in input mode"; getch(); exit(0); } cout<<"\nEnter the usn"; cin>>usn; i=0;//Loading the file to Main memory while(!in.eof()) { in.getline(s1[i].name,15,'|'); in.getline(s1[i].usn,15,'|'); in.getline(s1[i].age,5,'|'); in.getline(s1[i].sem,5,'|'); in.getline(s1[i]. branch, 15,'\n'); i++; } i--; for(j=0;j<i;j++) { if(strcmp(usn,s1[j].usn)==0) {

cout<<"\nThe old values of the record with usn "<<usn<<" are ";cout<<"\nname = "<< s1[j].name;cout<<"\nusn = "<< s1[j].usn;cout<<"\nage = "<< s1[j].age;cout<<"\nsem = "<< s1[j].sem;cout<<"\nbranch = "<< s1[j].branch;

cout<<"\nEnter the new values \n";cout<<"\nname = "; cin>>s1[j].name;cout<<"\nusn = "; cin>>s1[j].usn;cout<<"\nage = "; cin>>s1[j].age;



cout<<"\nsem = "; cin>>s1[j].sem;cout<<"\nbranch= "; cin>>s1[j].branch;break;

} } if(j==i) { cout<<"\n Record with usn "<<usn<<" is not present"; getch(); return; } in.close();

fstream out1; out1.open("student.txt",ios::out);

if(!out1) { cout<<"\nUnable to open file in output mode"; getch(); return; }

for(j=0;j<i;j++) { out1<<s1[j].name<<'|'<<s1[j].usn<<'|'<<s1[j].age<<'|'<<s1[j].sem<<'|'<<s1[j].sem<<'|'<<s1[j].branch<<'\n'; } out1.close();}

void main(){ fstream in; fstream out; int ch; out.open("student.txt",ios::out); if(!in) { cout<<"\n\nCannot open the file in output mode"; getch(); exit(0); } out.close();

for(;;) { clrscr(); cout<<"\n O:exit\n 1: write to file\n 2:display the file"

<<"\n 3:modify the file\n 4:search"; cout<<"\n\n Enter the choice: "; cin>>ch;



switch(ch) { case 1: writeRecord();break; case 2: displayFile();break; case 3: modify();break; case 4: search (); break; case 0: exit(0); default: cout<<"\nInvalid input....";break; } }}

4. Write a C++ program to write student objects with Variable – Length records using any suitable record structure and to read from this file a student record using RRN



#include<iostream.h>#include<fstream.h>#define SIZEOFRECORD 66 int no_of_records; class student{ public:

char name[15], usn[15], branch[15], sem[15];}; void displayontoterminal(student); void pack(student); void writefrombuffertofile(char[]); void unpack(char *buffer)

{student stu; int i=0,j=0,count=0;char temp[16];while(buffer[i]!='!')

{ j=0; while(buffer[i]!='|') temp[j++]=buffer[i++]; i++; count++; temp[j]='\0'; switch(count){ case 1 : strcpy(stu.name,temp);

break; case 2 : strcpy(stu.usn,temp);

break; case 3 : strcpy(stu.branch,temp);

break; case 4 : strcpy(stu.sem,temp);

break;}

}

displayontoterminal(stu);}void writetofile(){ student stu; cout<<"Enter the name of the student\n";

cin>>stu.name; cout<<"Enter the usn of the student"; cin>>stu.usn; cout<<"Enter the branch of the student\n"; cin>>stu.branch;



cout<<"Enter the semester of the student\n"; cin>>stu.sem; pack(stu);}void pack(student stu){ char buffer[66]; strcpy(buffer,stu.name); strcat(buffer,"|"); strcat(buffer,stu.usn); strcat(buffer,"|"); strcat(buffer,stu.branch); strcat(buffer,"|"); strcat(buffer,stu.sem); strcat(buffer,"|");/* cout<<"The packed data is\n"; * cout<<buffer;*/ int count=strlen(buffer);

for(int k=0;k<65-count;k++)strcat(buffer,"!"); strcat(buffer,"\n");writefrombuffertofile(buffer);

} void accessrecordbyRRN(){ int RRN;

char buffer[65]; cout<<"Enter the required Record Number\n"; cin>>RRN; if(RRN > no_of_records)

{ cout<<"\n Invalid Record no.!!!";

return;

}

int required_record_offset = ((RRN-1)*SIZEOFRECORD); ifstream readfromfile("puru.txt",ios::in); readfromfile.seekg(required_record_offset,ios::beg); readfromfile.getline(buffer,65,'\n'); cout<<"The record is\n"; cout<<buffer<<"\n"; unpack(buffer); readfromfile.close();}void writefrombuffertofile(char *buffer){ ofstream writetofile("puru.txt",ios::app);



writetofile<<buffer; writetofile.close(); no_of_records++;}void displayontoterminal(student stu){ cout<<"Name\t\t\tusn\t\t\tBranch\t\t\tSemester\t\t\t\n"; cout<<stu.name<<"\t\t\t"<<stu.usn<<"\t\t\t"<<stu.branch<<"\t\t\t"<<stu.sem<<endl;}

int main(){ int ch=1; while(ch) { cout<<"\n Enter 1. write to the file \n 2. Access record by RRN \n 3. Exit\n Enterur choice:";

cin>>ch;switch(ch)

{ case 1:

writetofile();break;

case 2:accessrecordbyRRN();break;

case 3: exit(0); }

}return 0;}

5. Write a C++ program to implement simple index on primary key for a file of student objects. Implement add ( ), search ( ), delete ( ) using the index.



include<iostream>#include<string.h>#include<fstream>#include<stdlib.h>using namespace std;//Record specificationclass record{ public: char age[5];

char usn[20],name[20],branch[5]; char sem[2];

}rec[20];

char st_no[5];int no;

void retrieve_details(){ fstream file2; char name[20],usn[20],branch[5]; char ind[5],age[5],sem[5]; file2.open("record.txt",ios::in); for(int i=0;i<no;i++) //Unpacking record data { file2.getline(ind,5,'|'); file2.getline(usn,20,'|'); file2.getline(name,20,'|'); file2.getline(age,5,'|'); file2.getline(sem,5,'|'); file2.getline(branch,5,'\n'); if(strcmp(ind,st_no)==0) //Required record found- so print details {

cout<<"\n\n"<<"Student details are: "; cout<<"\n\nUSN: "<<usn<<"\nName: "<<name<<"\nAge: "<<age<<"\nSem: "<<sem<<"\

nBranch: "<<branch<<"\n"; } } file2.close();}

void delete_record(char usno[]){ int i; fstream file1, file2; char age[5],sem[5],branch[5],usn[20],name[20],ind[5]; file2.open("record.txt",ios::in); for(i=0;i<no;i++) //Unpack records { file2.getline(ind,5,'|'); file2.getline(usn,20,'|'); file2.getline(name,20,'|');



file2.getline(age,5,'|'); file2.getline(sem,5,'|'); file2.getline(branch,5,'\n');

strcpy(rec[i].usn,usn); strcpy(rec[i].name,name); strcpy(rec[i].age,age); strcpy(rec[i].sem,sem); strcpy(rec[i].branch,branch); } int flag=-1; for(i=0;i<no;i++) //Check for the record's existence { if(strcmp(rec[i].usn,usno)==0) flag=i; } if(flag==-1) //Record not found { cout<<"Error !\n"; return; } if(flag==(no-1)) //Delete found record { no--; cout<<"Deleted !\n"; return; } for(i=flag;i<no;i++) { rec[i]=rec[i+1]; } no--; cout<<"\nDeleted !\n"; file2.close(); file1.open("index.txt",ios::out); //Open index and record files file2.open("record.txt",ios::out); //After deletion for(i=0;i<no;i++) //Pack index n record data onto files { file1<<rec[i].usn<<"|"<<i<<"\n"; file2<<i<<"|"<<rec[i].usn<<"|"<<rec[i].name<<"|"<<rec[i].age<<"|"<<rec[i].sem<<"|"<<rec[i].branch<<"\n"; } file1.close(); file2.close(); return;}

int main(){ fstream file1,file2; int ch;



char rt_usn[20],st_usn[20]; char ind[2],name[20],age[2],sem[5],branch[5]; int i,flag,flag1; file1.open("index.txt",ios::out); file2.open("record.txt",ios::out); if(!file1 || !file2) { cout<<"File creation Error! \n"; exit(0); } for(;;) { cout<<"\n1: Add Record"

<<"\n2: Search Record" <<"\n3: Delete Record" <<"\n4: Display Record";

cin>>ch; switch(ch) {

case 1: cout<<"Enter the no. of students : "; cin>>no; cout<<"Enter the details:\n"; for(i=0;i<no;i++) //Pack data onto the index and record files { //USN is the indexed data cout<<"\nName: "; cin>>rec[i].name; cout<<"Age: "; cin>>rec[i].age; cout<<"USN: "; cin>>rec[i].usn; cout<<"Sem: "; cin>>rec[i].sem; cout<<"Branch: "; cin>>rec[i].branch;

file1<<rec[i].usn<<"|"<<i<<"\n";file2<<i<<"|"<<rec[i].usn<<"|"<<rec[i].name<<"|"<<rec[i].age<<"|"<<rec[i].sem<<"|"<<rec[i].branch<<"\n";

} file1.close(); file2.close(); break;

case 2: cout<<"Enter USN whose record is to be displayed: "; cin>>st_usn; file1.open("index.txt",ios::in); if(!file1) { cout<<"\nError !\n"; exit(0); } flag1=0; for(i=0;i<no;i++) { file1.getline(rt_usn,20,'|'); //Unpack index file and file1.getline(st_no,4,'\n'); //look for a match in the USN if(strcmp(st_usn,rt_usn)==0) { retrieve_details(); //Retrieve details if index found



flag1=1; } } if(!flag1) cout<<"Record search failed!\n"; file1.close(); break;

case 3: cout<<"Enter USN whose record is to be deleted: "; cin>>st_usn; file1.open("index.txt", ios::in); if(!file1) { cout<<"Error! \n"; exit(0); } flag=0; for(i=0;i<no;i++) { file1.getline(rt_usn,20,'|'); //Search index file and file1.getline(st_no,4,'\n'); //call del if index found if(strcmp(st_usn, rt_usn)==0) { delete_record(rt_usn); flag=1; } } if(!flag) cout<<"Deletion Failed\n"; file1.close(); break;

case 4: for(i=0;i<no;i++) { cout<<"\n\n USN: "<<rec[i].usn <<"\n Name: "<<rec[i].name <<"\n Age: "<<rec[i].age <<"\n Sem: "<<rec[i].sem <<"\n Branch: "<<rec[i].branch; } break;

default: cout<<"Invalid choice"; exit(0); break;

} }}

OR



#include<iostream.h>#include<string.h>#include<fstream.h>#include<stdlib.h>

//Record specificationclass record{ public: char age[5];

char usn[20],name[20],branch[5]; char sem[2];

}rec[20];

char st_no[5];int no;

void retrieve_details(){ fstream file2; char name[20],usn[20],branch[5]; char ind[5],age[5],sem[5]; file2.open("record.txt",ios::in); for(int i=0;i<no;i++) //Unpacking record data { file2.getline(ind,5,'|'); file2.getline(usn,20,'|'); file2.getline(name,20,'|'); file2.getline(age,5,'|'); file2.getline(sem,5,'|'); file2.getline(branch,5,'\n'); if(strcmp(ind,st_no)==0) //Required record found- so print details {

cout<<"\n\n"<<"Student details are: "; cout<<"\n\nUSN: "<<usn<<"\nName: "<<name<<"\nAge: "<<age<<"\nSem: "<<sem<<"\

nBranch: "<<branch<<"\n"; } } file2.close();}

void delete_record(char usno[]){ int i; fstream file1, file2; char age[5],sem[5],branch[5],usn[20],name[20],ind[5]; file2.open("record.txt",ios::in); for(i=0;i<no;i++) //Unpack records { file2.getline(ind,5,'|'); file2.getline(usn,20,'|'); file2.getline(name,20,'|'); file2.getline(age,5,'|');



file2.getline(sem,5,'|'); file2.getline(branch,5,'\n');

strcpy(rec[i].usn,usn); strcpy(rec[i].name,name); strcpy(rec[i].age,age); strcpy(rec[i].sem,sem); strcpy(rec[i].branch,branch); } int flag=-1; for(i=0;i<no;i++) //Check for the record's existence { if(strcmp(rec[i].usn,usno)==0) flag=i; } if(flag==-1) //Record not found { cout<<"Error !\n"; return; } if(flag==(no-1)) //Delete found record { no--; cout<<"Deleted !\n"; return; } for(i=flag;i<no;i++) { rec[i]=rec[i+1]; } no--; cout<<"\nDeleted !\n"; file2.close(); file1.open("index.txt",ios::out); //Open index and record files file2.open("record.txt",ios::out); //After deletion for(i=0;i<no;i++) //Pack index n record data onto files { file1<<rec[i].usn<<"|"<<i<<"\n"; file2<<i<<"|"<<rec[i].usn<<"|"<<rec[i].name<<"|"<<rec[i].age<<"|"<<rec[i].sem<<"|"<<rec[i].branch<<"\n"; } file1.close(); file2.close(); return;}

int main(){ fstream file1,file2; int ch; char rt_usn[20],st_usn[20];



char ind[2],name[20],age[2],sem[5],branch[5]; int i,flag,flag1; file1.open("index.txt",ios::out); file2.open("record.txt",ios::out); if(!file1 || !file2) { cout<<"File creation Error! \n"; exit(0); } for(;;) { cout<<"\n1: Add Record"

<<"\n2: Search Record" <<"\n3: Delete Record" <<"\n4: Display Record";

cin>>ch; switch(ch) {

case 1: cout<<"Enter the no. of students : "; cin>>no; cout<<"Enter the details:\n"; for(i=0;i<no;i++) //Pack data onto the index and record files { //USN is the indexed data cout<<"\nName: "; cin>>rec[i].name; cout<<"Age: "; cin>>rec[i].age; cout<<"USN: "; cin>>rec[i].usn; cout<<"Sem: "; cin>>rec[i].sem; cout<<"Branch: "; cin>>rec[i].branch;

file1<<rec[i].usn<<"|"<<i<<"\n";file2<<i<<"|"<<rec[i].usn<<"|"<<rec[i].name<<"|"<<rec[i].age<<"|"<<rec[i].sem<<"|"<<rec[i].branch<<"\n";

} file1.close(); file2.close(); break;

case 2: cout<<"Enter USN whose record is to be displayed: "; cin>>st_usn; file1.open("index.txt",ios::in); if(!file1) { cout<<"\nError !\n"; exit(0); } flag1=0; for(i=0;i<no;i++) { file1.getline(rt_usn,20,'|'); //Unpack index file and file1.getline(st_no,4,'\n'); //look for a match in the USN if(strcmp(st_usn,rt_usn)==0) { retrieve_details(); //Retrieve details if index found flag1=1;



} } if(!flag1) cout<<"Record search failed!\n"; file1.close(); break;

case 3: cout<<"Enter USN whose record is to be deleted: "; cin>>st_usn; file1.open("index.txt", ios::in); if(!file1) { cout<<"Error! \n"; exit(0); } flag=0; for(i=0;i<no;i++) { file1.getline(rt_usn,20,'|'); //Search index file and file1.getline(st_no,4,'\n'); //call del if index found if(strcmp(st_usn, rt_usn)==0) { delete_record(rt_usn); flag=1; } } if(!flag) cout<<"Deletion Failed\n"; file1.close(); break;

case 4: for(i=0;i<no;i++) { cout<<"\n\n USN: "<<rec[i].usn <<"\n Name: "<<rec[i].name <<"\n Age: "<<rec[i].age <<"\n Sem: "<<rec[i].sem <<"\n Branch: "<<rec[i].branch; } break;

default: cout<<"Invalid choice"; exit(0); break;

} }}

6. Write a C++ program to implement index on secondary key, the name, for a file of student objects. Implement add ( ), search ( ), delete ( ) using the secondary index.



#include<iostream>#include<string.h>#include<fstream>#include<stdlib.h>using namespace std;//using namespace std;

class record{ public: char age[5];

char usn[20],name[20],branch[5]; char sem[2];}rec[20],found[20];

char st_no[5],rt_name[20];int no;

void sort_records(){ int i,j; record temp; for(i=0;i<no-1;i++) for(j=0;j<no-i-1;j++)

if(strcmp(rec[j].name, rec[j+1].name) > 0) { temp=rec[j]; rec[j]=rec[j+1]; rec[j+1]=temp; }

}

void create_indexfile(){ fstream index,index2; int i; index.open("secindex.txt",ios::out); index2.open("record.txt",ios::out); for(i=0;i<no;i++) { index<<rec[i].name<<"|"

<<rec[i].usn<<"|"<<i<<"\n"; index2<<i<<"|"<<rec[i].usn<<"|"<<rec[i].name<<"|"<<rec[i].age<<"|"

<<rec[i].sem<<"|"<<rec[i].branch<<"\n"; }}

void retrieve_record(char* index){ fstream file; int i; char ind[2],usn[20],name[20],age[3],sem[3],branch[10]; file.open("record.txt",ios::in); for(i=0;i<no;i++)



{ file.getline(ind,4,'|'); file.getline(usn,20,'|'); file.getline(name,20,'|'); file.getline(age,4,'|'); file.getline(sem,4,'|'); file.getline(branch,5,'\n'); if(strcmp(index,ind) == 0)

cout<<"\nUSN: "<<usn <<"\nName: "<<name <<"\nAge: "<<age <<"\nSem: "<<sem <<"\nBranch: "<<branch;

} file.close(); return;}

void retrieve_details(){ int k=0,i; char name[20],usn[20],ind[2]; char chusn[20]; char index[20][20]; fstream file; file.open("secindex.txt",ios::in); for(i=0;i<no;i++) { file.getline(name,20,'|'); file.getline(usn,20,'|'); file.getline(ind,4,'\n'); if(strcmp(name,rt_name) == 0) {

strcpy(found[k].name,name); strcpy(found[k].usn,usn); strcpy(index[k],ind); k++;

} } file.close(); if(k==1) { retrieve_record(index[0]); return; } else { cout<<"Please choose the candidate's USN: \n"; for(i=0;i<k;i++) cout<<"Name: "<<found[i].name<<" USN: "<<found[i].usn<<endl; } cin>>chusn;



for(i=0;i<k;i++) { if(strcmp(chusn,found[i].usn) == 0) {

retrieve_record(index[i]); return;

} } cout<<"Invalid Entry! \n"; return;}

void delete_record(char indx[]){ int i; fstream file1,file2; char age[5],sem[5],branch[5],usn[20],name[20],ind[5]; char index[20][20]; file2.open("record.txt",ios::in); for(i=0;i<no;i++) { file2.getline(ind,4,'|'); file2.getline(usn,20,'|'); file2.getline(name,20,'|'); file2.getline(age,5,'|'); file2.getline(sem,5,'|'); file2.getline(branch,8,'\n'); strcpy(index[i],ind); strcpy(rec[i].usn,usn); strcpy(rec[i].name,name); strcpy(rec[i].age,age); strcpy(rec[i].sem,sem); strcpy(rec[i].branch,branch); } int flag=-1; for(i=0;i<no;i++) { if(strcmp(index[i],indx) == 0) flag=i; } if(flag==-1) { cout<<"Error!\n"; return; } if(flag==(no-1)) { no--; cout<<"Deleted!\n"; return; } for(i=flag;i<no;i++)



{ rec[i]=rec[i+1]; } no--; cout<<"Deleted!\n"; file2.close(); file1.open("secindex.txt",ios::out); file2.open("record.txt",ios::out); for(i=0;i<no;i++) { file1<<rec[i].name<<"|"<<rec[i].usn<<"|"<<i<<"\n";

file2<<i<<"|"<<rec[i].usn<<"|"<<rec[i].name<<"|" <<rec[i].age<<"|"<<rec[i].sem<<"|"<<rec[i].branch<<"\n";

} file1.close(); file2.close(); return;}

void delete_index(char* nam){ fstream file; int i; int k=0; char name[20],usn[20],ind[5],index[20][20],chusn[20]; file.open("secindex.txt",ios::in); for(i=0;i<no;i++) { file.getline(name,20,'|'); file.getline(usn,20,'|'); file.getline(ind,4,'\n'); if(strcmp(nam,name)==0) {


} } file.close(); if(k==1) { delete_record(index[0]); return; } else { cout<<"Please choose the candidate's USN: \n"; for(i=0;i<k;i++) {



cout<<"Name: "<<found[i].name<<" USN: "<<found[i].usn<<endl; } } cin>>chusn; for(i=0;i<k;i++) { if(strcmp(chusn,found[i].usn)==0) {

delete_record(index[i]); return;

} } cout<<"Invalid Entry!\n"; return;}

int main(){ fstream file1,file2; int ch; char rt_usn[20],st_name[20],st_usn[20]; char ind[2],name[20],age[2],sem[5],branch[5]; int i,flag,flag1; file1.open("index.txt",ios::out); file2.open("record.txt",ios::out); if(!file1 || !file2) { cout<<"File creation Error!\n"; exit(0); } for(;;) { cout<<"\nl:Add Record\n 2:Search Record"

<<"\n3:Delete Record\n 4:Display Record\n"; cin>>ch; switch(ch) {

case 1: cout<<"Enter the no. of students : "; cin>>no; cout<<"Enter the details :\n"; for(i=0;i<no;i++) { cout<<"\nName : "; cin>>rec[i].name; cout<<"Age : "; cin>>rec[i].age; cout<<"USN : "; cin>>rec[i].usn; cout<<"Sem : "; cin>>rec[i].sem; cout<<"Branch : "; cin>>rec[i].branch; } sort_records(); create_indexfile(); file1.close (); file2.close(); break;



case 2: cout<<"Enter name of the student whose record is to be displayed\n"; cin>>st_name; file1.open("secindex.txt",ios::in); if(!file1) { cout<<"Error !\n"; exit(0); } flag1=0; for(i=0;i<no;i++) { file1.getline(rt_name,20,'|'); file1.getline(rt_usn,20,'|'); file1.getline(st_no,4,'\n');

if(strcmp(st_name,rt_name)==0) {

retrieve_details();flag1=1;goto one;

} } one: if(!flag1)

cout<<"Record search failed !\n"; file1.close(); break;

case 3: cout<<"Enter name of student whose record is to be deleted\n"; cin>>st_name; file1.open("secindex.txt",ios::in); if(!file1) { cout<<"Error !\n"; exit(0); } flag=0; for(i=0;i<no;i++) { file1.getline(rt_name,20,'|'); file1.getline(rt_usn,20,'|'); file1.getline(ind,4,'\n');

if(strcmp(st_name,rt_name) == 0) { delete_index(rt_name); flag=1; } } if(!flag) cout<<"Deletion failed !\n"; file1.close();



break;

case 4: for(i=0;i<no;i++) { cout<<"\n\nUSN : "<<rec[i].usn <<"\nName: "<<rec[i].name <<"\nAge : "<<rec[i].age <<"\nSem : "<<rec[i].sem <<"\nBranch : "<<rec[i].branch<<"\n"; } break;

default: cout<<"Invalid option !\n"; exit(0); break;

} } return 0;}

OR

#include<iostream.h>#include<string.h>#include<fstream.h>#include<stdlib.h>

//using namespace std;

class record{ public: char age[5];

char usn[20],name[20],branch[5]; char sem[2];}rec[20],found[20];

char st_no[5],rt_name[20];int no;

void sort_records(){ int i,j; record temp; for(i=0;i<no-1;i++) for(j=0;j<no-i-1;j++)

if(strcmp(rec[j].name, rec[j+1].name) > 0) { temp=rec[j]; rec[j]=rec[j+1]; rec[j+1]=temp; }

}



void create_indexfile(){ fstream index,index2; int i; index.open("secindex.txt",ios::out); index2.open("record.txt",ios::out); for(i=0;i<no;i++) { index<<rec[i].name<<"|"

<<rec[i].usn<<"|"<<i<<"\n"; index2<<i<<"|"<<rec[i].usn<<"|"<<rec[i].name<<"|"<<rec[i].age<<"|"

<<rec[i].sem<<"|"<<rec[i].branch<<"\n"; }}

void retrieve_record(char* index){ fstream file; int i; char ind[2],usn[20],name[20],age[3],sem[3],branch[10]; file.open("record.txt",ios::in); for(i=0;i<no;i++) { file.getline(ind,4,'|'); file.getline(usn,20,'|'); file.getline(name,20,'|'); file.getline(age,4,'|'); file.getline(sem,4,'|'); file.getline(branch,5,'\n'); if(strcmp(index,ind) == 0)

cout<<"\nUSN: "<<usn <<"\nName: "<<name <<"\nAge: "<<age <<"\nSem: "<<sem <<"\nBranch: "<<branch;

} file.close(); return;}

void retrieve_details(){ int k=0,i; char name[20],usn[20],ind[2]; char chusn[20]; char index[20][20]; fstream file; file.open("secindex.txt",ios::in); for(i=0;i<no;i++) { file.getline(name,20,'|'); file.getline(usn,20,'|');



file.getline(ind,4,'\n'); if(strcmp(name,rt_name) == 0) {


} } file.close(); if(k==1) { retrieve_record(index[0]); return; } else { cout<<"Please choose the candidate's USN: \n"; for(i=0;i<k;i++) cout<<"Name: "<<found[i].name<<" USN: "<<found[i].usn<<endl; } cin>>chusn; for(i=0;i<k;i++) { if(strcmp(chusn,found[i].usn) == 0) {

retrieve_record(index[i]); return;

} } cout<<"Invalid Entry! \n"; return;}

void delete_record(char indx[]){ int i; fstream file1,file2; char age[5],sem[5],branch[5],usn[20],name[20],ind[5]; char index[20][20]; file2.open("record.txt",ios::in); for(i=0;i<no;i++) { file2.getline(ind,4,'|'); file2.getline(usn,20,'|'); file2.getline(name,20,'|'); file2.getline(age,5,'|'); file2.getline(sem,5,'|'); file2.getline(branch,8,'\n'); strcpy(index[i],ind); strcpy(rec[i].usn,usn); strcpy(rec[i].name,name);



strcpy(rec[i].age,age); strcpy(rec[i].sem,sem); strcpy(rec[i].branch,branch); } int flag=-1; for(i=0;i<no;i++) { if(strcmp(index[i],indx) == 0) flag=i; } if(flag==-1) { cout<<"Error!\n"; return; } if(flag==(no-1)) { no--; cout<<"Deleted!\n"; return; } for(i=flag;i<no;i++) { rec[i]=rec[i+1]; } no--; cout<<"Deleted!\n"; file2.close(); file1.open("secindex.txt",ios::out); file2.open("record.txt",ios::out); for(i=0;i<no;i++) { file1<<rec[i].name<<"|"<<rec[i].usn<<"|"<<i<<"\n";

file2<<i<<"|"<<rec[i].usn<<"|"<<rec[i].name<<"|" <<rec[i].age<<"|"<<rec[i].sem<<"|"<<rec[i].branch<<"\n";

} file1.close(); file2.close(); return;}

void delete_index(char* nam){ fstream file; int i; int k=0; char name[20],usn[20],ind[5],index[20][20],chusn[20]; file.open("secindex.txt",ios::in); for(i=0;i<no;i++) {



file.getline(name,20,'|'); file.getline(usn,20,'|'); file.getline(ind,4,'\n'); if(strcmp(nam,name)==0) {


} } file.close(); if(k==1) { delete_record(index[0]); return; } else { cout<<"Please choose the candidate's USN: \n"; for(i=0;i<k;i++) {

cout<<"Name: "<<found[i].name<<" USN: "<<found[i].usn<<endl; } } cin>>chusn; for(i=0;i<k;i++) { if(strcmp(chusn,found[i].usn)==0) {

delete_record(index[i]); return;

} } cout<<"Invalid Entry!\n"; return;}

int main(){ fstream file1,file2; int ch; char rt_usn[20],st_name[20],st_usn[20]; char ind[2],name[20],age[2],sem[5],branch[5]; int i,flag,flag1; file1.open("index.txt",ios::out); file2.open("record.txt",ios::out); if(!file1 || !file2) { cout<<"File creation Error!\n"; exit(0); }



for(;;) { cout<<"\nl:Add Record\n 2:Search Record"

<<"\n3:Delete Record\n 4:Display Record\n"; cin>>ch; switch(ch) {

case 1: cout<<"Enter the no. of students : "; cin>>no; cout<<"Enter the details :\n"; for(i=0;i<no;i++) { cout<<"\nName : "; cin>>rec[i].name; cout<<"Age : "; cin>>rec[i].age; cout<<"USN : "; cin>>rec[i].usn; cout<<"Sem : "; cin>>rec[i].sem; cout<<"Branch : "; cin>>rec[i].branch; } sort_records(); create_indexfile(); file1.close (); file2.close(); break;

case 2: cout<<"Enter name of the student whose record is to be displayed\n"; cin>>st_name; file1.open("secindex.txt",ios::in); if(!file1) { cout<<"Error !\n"; exit(0); } flag1=0; for(i=0;i<no;i++) { file1.getline(rt_name,20,'|'); file1.getline(rt_usn,20,'|'); file1.getline(st_no,4,'\n');

if(strcmp(st_name,rt_name)==0) {

retrieve_details();flag1=1;goto one;

} } one: if(!flag1)

cout<<"Record search failed !\n"; file1.close(); break;

case 3: cout<<"Enter name of student whose record is to be deleted\n"; cin>>st_name;



file1.open("secindex.txt",ios::in); if(!file1) { cout<<"Error !\n"; exit(0); } flag=0; for(i=0;i<no;i++) { file1.getline(rt_name,20,'|'); file1.getline(rt_usn,20,'|'); file1.getline(ind,4,'\n');

if(strcmp(st_name,rt_name) == 0) { delete_index(rt_name); flag=1; } } if(!flag) cout<<"Deletion failed !\n"; file1.close(); break;

case 4: for(i=0;i<no;i++) { cout<<"\n\nUSN : "<<rec[i].usn <<"\nName: "<<rec[i].name <<"\nAge : "<<rec[i].age <<"\nSem : "<<rec[i].sem <<"\nBranch : "<<rec[i].branch<<"\n"; } break;

default: cout<<"Invalid option !\n"; exit(0); break;

} } return 0;}

7. Write a C++ program to read two lists of names and then match the names in the two lists using Cosequential Match based on a single loop. Output the names common to both the lists



#include<stdio.h>#include<stdlib.h>#include<string.h>#include<fstream.h>#include<iostream.h>

void writeLists(){ fstream out1,out2; int i,m,n; char name[20];

out1.open("file1.txt",ios::out); out2.open("file2.txt",ios::out);

if( (!out1) || (!out2) ) { cout<<"Unable to open one of the list files"; getch(); exit(0); }

cout<<"Enter no. of names you want to enter in file1"; cin>>m; cout<<"\nEnter the names in ascending order\n"; for(i-0;i<m;i++) { cin>>name; out1<<name; out1<<'\n'; }

cout<<"Enter no. of names you want to enter in file2"; cin>>n; cout<<"\nEnter the names in ascending order \n"; for(i=0;i<n;i++) { cin>>name; out2<<name; out2<<'\n'; } out1.close(); out2.close();}

void main(){ char list1[100][20], list2[100][20]; int i,j,m,n; clrscr(); fstream out1,out2,out3;

writeLists();



out1.open("file1.txt",ios::in); out2.open("file2.txt",ios::in); out3.open("file3.txt",ios::out);

if( (!out3) || (!out1) || (!out2) ) { printf("Unable to open one of the file"); getch(); exit(0); } clrscr(); m=0; n=0; while(!out1.eof()) { out1.getline(list1[m],20,'\n'); cout<<list1[m]; m++; } while(!out2.eof()) { out2.getline(list2[n],20,'\n'); cout<<list2[n]; n++; } m--; n--; i=0; j=0;

cout<<"\nElements common to both files are: \n "; while(i<m && j<n) { if( strcmp(list1[i],list2[j]) == 0 ) {

out3<<list1[i]; cout<<list1[i]<<"\n"; out3<<'\n'; i++; j++;

} else if( strcmp(list1[i],list2[j]) < 0 )

i++; else

j++; } getch();}8. Write a C++ program to read k Lists of names and merge them using k-way merge algorithm with k = 8.

#include<iostream.h>



#include<fstream.h>#include<string.h>

// Record specification

class record{

public: char name[20];char usn[20];

}rec[20];

int no;

fstream file[8];

//The first 8 files

char fname[8][8] = {"l.txt","2.txt","3.txt","4.txt","5.txt","6.txt","7.txt","8.txt"};

void merge_file(char* file1, char* file2, char* filename){

record recrd[20];int k; k=0;fstream f1,f2;f1.open(file1,ios::in); //open the first filef2.open(file2,ios::in); //open the second filewhile(!f1.eof()) //Unpack and retrieve first file{

f1.getline(recrd[k].name,20,'|'); f1.getline(recrd[k++].usn,20,'\n');

}while(!f2.eof()) //Unpack and retrieve second file{

f2.getline(recrd[k].name,20,'|');f2.getline(recrd [k++].usn, 20,'\n');

}record temp;int t,y;for(t=0;t<k-2;t++) //Sort the retrieved recordsfor(y=0;y<k-t-2;y++)if(strcmp(recrd[y].name,recrd[y+1].name)>0){

temp=recrd[y];recrd[y]=recrd[y+1];recrd[y+1]=temp;

}fstream temp1;temp1.open(filename,ios::out); //Open the file to be packed intofor(t=1;t<k-1;t++) //Pack the sorted records onto the file

temp1<<recrd[t].name<<"|"<<recrd[t].usn<<"\n";f1.close();



f2.close();temp1.close();return;

}void kwaymerge(){

char filename[7][20]={"ll.txt","22.txt","33.txt","44.txt","lll.txt","222.txt","llll.txt"};int i;int k;k=8;for(i=0;i<8;i+=2) //Merge and sort the 8 original files onto{ //the four files indicated {ll.txt,22.txt....}

merge_file(fname[i],fname[i+1],filename[k++]);}k=4;for(i=0;i<4;i+=2) //Merge and sort the four files onto lll.txt and 222.txt{

merge_file(filename[i],filename[i+1],filename[k++]);}//Merge and sort the two files onto the llll.txt filemerge_file(filename[4],filename[5],filename[6]);return;

}

int main(){

int i;cout<<"Enter the no. of records : ";cin>>no;cout<<"\nEnter the details : \n";for(i=0;i<8;i++) //Create 8 files to store the split data

file[i].open(fname[i],ios::out);for(i=0;i<8;i++) //Split and pack data onto the files{

cout<<"Name :"; cin>>rec[i].name;cout<<"USN : ";cin>>rec[i].usn;file[i%8]<<rec[i].name<<'|'<<rec[i].usn<<"\n";

}for(i=0;i<8;i++)file[i].close();kwaymerge(); //Mergefstream result;result.open("llll.txt",ios::in);cout<<"\nSorted Records : \n";char name[20],usn[20];for(i=0;i<8;i++) //Unpack the sorted records and dispL{

result.getline(name,20,'|');result.getline(usn,20,'\n');cout<<"\nName : "<<name<<"\nUSN : "<<usn<<"\n";

}return 0;



}

9. Write a C++ program to implement B-Tree for a given set of integers and its operations insert ( ) and search ( ). Display the tree.

// Program which maintains a B-tree of order 5.



#include<iostream.h>#include<conio.h>#include<stdlib.h>#include<alloc.h>

const int MAX = 4 ;const int MIN = 2 ;

struct btnode{ int count; int value[MAX + 1]; btnode *child[MAX + 1];};

class btree{

private : btnode *root ;public : btree( ) ;void insert(int val) ;int setval(int val, btnode *n, int *p, btnode **c);static btnode *search (int val, btnode *root, int *pos);static int searchnode(int val, btnode *n, int *pos);void iskeypresent( int val) ;void fillnode( int val, btnode *c, btnode *n, int k );void split( int val, btnode *c, btnode *n, int k, int *y, btnode **newnode );void clear( btnode *root, int k );void copysucc( btnode *root, int i );void merge( int k ) ;void show( );static void display( btnode *root );static void deltree( btnode *root );~btree( );

};

// Initializes data memberbtree :: btree( ){

root=NULL;}

// searches a key and checks whether it is present or notvoid btree :: iskeypresent(int val){

int i ;if( searchnode ( val, root, &i ) )

cout<< "Key found "<<endl;else

cout<< "Key Not found "<<endl;}



// Inserts a value in the B-treevoid btree :: insert ( int val ){

int i ;btnode *c, *n ;int flag ;flag = setval( val, root, &i, &c ) ;if( flag ){

n = new btnode ;n -> count = 1 ;n -> value[1] = i ;n -> child[0] = root ;n -> child[1] = c ;root = n ;

}}

// Sets the value in the nodeint btree :: setval ( int val, btnode *n, int *p, btnode **c){

int k ;if ( n == NULL ){

*p = val ;*c = NULL ;return 1 ;

}else{

if( searchnode ( val, n, &k ) ){

cout << endl << "Key value already exists";return 0 ;

}if ( setval ( val, n -> child[k], p, c ) ){

if ( n -> count < MAX ){

fillnode ( *p, *c, n, k ) ;return 0 ;

}else{

split ( *p, *c, n, k, p, c ) ;return 1 ;

}}return(0);}

}



// Searches value in the nodebtnode * btree :: search ( int val, btnode *root, int *pos ){

if ( root == NULL ) return NULL ;else{

if ( searchnode ( val, root, pos ) )return root ;

elsereturn search ( val, root -> child[*pos], pos ) ;

}}

// searches for the nodeint btree :: searchnode ( int val, btnode *n, int *pos ){ //this condition is used to decide the traversal

if ( val < n -> value[1] ){

*pos = 0 ;return 0 ;

}else{

*pos = n -> count ;while ( ( val < n -> value[*pos] ) && *pos > 1 )(*pos)-- ;

if ( val == n -> value[*pos] )return 1 ;else

return 0 ;}

}

// adjusts the value of the nodevoid btree :: fillnode ( int val, btnode *c, btnode *n, int k ){

int i ;for ( i = n -> count ; i > k ; i-- ){

n -> value[i + 1] = n -> value[i] ;n -> child[i + 1] = n -> child[i] ;

}n -> value[k + 1] = val ;n -> child[k + 1] = c ;n -> count++ ;

}

// splits the nodevoid btree :: split ( int val, btnode *c, btnode *n, int k, int *y, btnode **newnode )



{int i, mid ;if ( k <= MIN )

mid = MIN ;else

mid = MIN + 1 ;*newnode = new btnode ;for ( i = mid + 1 ; i <= MAX ; i++ ){

( *newnode ) -> value[i - mid] = n -> value[i] ;( *newnode ) -> child[i - mid] = n -> child[i] ;

}( *newnode ) -> count = MAX - mid ;n -> count = mid ;

if ( k <= MIN )fillnode ( val, c, n, k ) ;

elsefillnode ( val, c, *newnode, k - mid ) ;*y = n -> value[n -> count] ;( *newnode ) -> child[0] = n -> child[n -> count] ;n -> count-- ;

}

// removes the value from the node and adjusts the valuesvoid btree :: clear ( btnode *root, int k ){

int i ;for ( i = k + 1 ; i <= root -> count ; i++ ){

root -> value[i - 1] = root -> value[i] ;root -> child[i - 1] = root -> child[i] ;

}root -> count-- ;

}

// copies the successor of the value that is to be deletedvoid btree :: copysucc ( btnode *root, int i ){

btnode *temp = root -> child[i] ;while ( temp -> child[0] )temp = temp -> child[0] ;root -> value[i] = temp -> value[1] ;

}

// merges two nodesvoid btree :: merge ( int k ){

btnode *temp1, *temp2 ;temp1 = root -> child[k] ;temp2 = root -> child[k - 1] ;temp2 -> count++ ;temp2 -> value[temp2 -> count] = root -> value[k] ;



temp2 -> child [temp2 -> count] = root -> child[0] ;for ( int i = 1 ; i <= temp1 -> count ; i++ ){

temp2 -> count++ ;temp2 -> value[temp2 -> count] = temp1 -> value[i] ;temp2 -> child[temp2 -> count] = temp1 -> child[i] ;

}for ( i = k ; i < root -> count ; i++ ){

root -> value[i] = root -> value[i + 1] ;root -> child[i] = root -> child[i + 1] ;

}root -> count-- ;delete temp1 ;

}

// calls display( )void btree :: show( ){

display ( root ) ;}

// displays the B-treevoid btree :: display ( btnode *root ){

if ( root != NULL ){

for ( int i = 0 ; i < root -> count ; i++){

display ( root -> child[i] ) ;cout << root -> value[i + 1] << "\t";

}display ( root -> child [i] ) ;

}}

// deallocates memoryvoid btree :: deltree ( btnode *root ){

if ( root != NULL ){ for ( int i = 0 ; i < root -> count ; i++) {

deltree ( root -> child [i] ) ;delete ( root -> child[i] ) ;

} deltree ( root -> child[i] ) ; delete ( root -> child[i] ) ; }

}



btree :: ~btree( ){

deltree ( root ) ;}

void main( ){

btree b ;clrscr();int num;int choice=0;while (choice!=4){

cout<<endl<<"l - Insert"<<endl;cout<<"2 - Search"<<endl;cout<<"3 - Display"<<endl;cout<<"4 - Exit"<<endl;cout<<"Enter your choice"<<endl;cin>>choice;switch(choice){

case 1: cout<<"\nEnter the elements to be inseretd into b tree \n";cin>>num;b.insert ( num ) ;break;

case 2: cout<<"\nEnter the elements to be searched in b tree \n";cin>>num;b.iskeypresent ( num ) ;break;

case 3: b.show( ) ;break;

case 4: exit(0);default: cout<<"\nInvalid Option \n";

}}

}

10. Write a C++ program to implement B+ tree for a given set of integers and its operations insert ( ), and search ( ). Display the tree.

#include<iostream.h>



#include<math.h>#include<conio.h>struct node{ int ele[4]; int child[4]; node *next;};

class bptree{public: node *tree[20][20]; int count[20]; int leaf; int path[20]; node *head;

bptree(); node* create_node(); void insert(int); void main_search(int); void display_tree(); void insert_node(node*,int); void search(int); int search_node(node*,int); int nodefull(node*); void split(node*);};

bptree::bptree(){ leaf=-1; for(int i=0;i<10;i++) { count[i]=-1; path[i]=-1; } }

node* bptree::create_node(){ node *n; n= new node; for(int i=0;i<4;i++) { n->ele[i]=-1; n->child[i]=-1; } n->next=NULL; return n; }



void bptree::insert(int key){ int n,parent; node *first_node; if(leaf==-1) { first_node=create_node(); tree[0][0]=first_node; leaf++; count[0]++; first_node->ele[0]=key;

head=first_node; //header node of sequence set } else if(leaf==0) { if(nodefull(tree[0][0])) { path[leaf]=0; split(tree[0][0]); insert(key); } else insert_node(tree[0][0],key); }

else { search(key); n=path[leaf]; parent=path[leaf-1]; if((nodefull(tree[leaf][n]))) { split(tree[leaf][n]); insert(key); } else insert_node(tree[leaf][n],key); }}

void bptree::main_search(int key){ int flag=0,i; node *node1; search(key); node1=tree[leaf][path[leaf]];

for(i=0;node1->ele[i]!=-1;i++) if(node1->ele[i]==key) {



flag=1; break; } cout<<"\n The Path traversed is:"; for(i=0;path[i]!=-1;i++) cout<<path[i]<<"->"; if(flag) cout<<"\nElement Found"; else cout<<"\nNot Found";}

void bptree::display_tree(){ int i,j,k; for(i=0;i<=leaf;i++) { cout<<"\n\n Level-------------"<<i<<"\n"; for(j=0;j<=count[i];j++) {

if(i!=leaf) k=1;else k=0;

//print first element only at leaf level for(;tree[i][j]->ele[k] != -1;k++) cout<<""<<tree[i][j]->ele[k]; cout<<"\t"; } } }

void bptree::search(int key){ int i,j,temp; path[0]=0; //always start the path from root if(leaf) { j=0; for(i=0;i<leaf;i++) {

temp=search_node(tree[i][j],key); path[i+1]=temp; j=temp;

} }}

int bptree::search_node(node *node1,int key){ for(int i=0;i<4;i++) { if(key < node1->ele[i])



return node1->child[i]; if((key >= node1->ele[i]) && (key < node1->ele[i+1])) return node1->child[i]; else if(node1->ele[i+1] == -1) return node1->child[i]; }}

int bptree::nodefull(node *node1){ if(node1->ele[3]!=-1)return 1; else return 0;}

void bptree::insert_node(node *node1,int key) { int flag=0,count=-1,i,j,x,y,l; node *newnode, *parent;

for(i=0;i<4;i++) if(node1->ele[i]!=-1) ++count;

i=0; while(!flag && node1->ele[i] != -1) {

if(node1->ele[i] > key) { flag=1; for(int j=count; j>=i; j--)

node1->ele[j+1]=node1->ele[j]; node1->ele[i]=key; }i++;

} if(!flag)

node1->ele[count+1]=key; if(node1->ele[0]==key) {

for(i=leaf-1;i>=0;i--) { x=path[i+1]; if(tree[i][path[i]]->ele[x]>key) tree[i][path[i]]->ele[x]=key; else insert_node(tree[i][x],key); }

} for(i=0;i<=count+1;i++)

cout<<"\t\t"<<node1->ele[i];}

void bptree::split(node *oldnode){



node *newnode, *parent,*n1,*n2; node *temp; int i,j,k,n,t,x,y,pos; newnode=create_node(); newnode->ele[0]=oldnode->ele[2]; newnode->ele[1]=oldnode->ele[3]; oldnode->ele[2]=-1; oldnode->ele[3]=-1; t=count[leaf]; n=path[leaf]; for(i=t,j=t+1;i>n;i--,j--) tree[leaf][j]=tree[leaf][i];

newnode->next=tree[leaf][n]->next; tree[leaf][n]->next=newnode; tree[leaf][n+1]=newnode; count[leaf]++; x=leaf; if(count[leaf]+1==1) t=1; else t=log(count[leaf]+1)/log(2); if(t!=leaf) { ++leaf; count[leaf]=count[x]; for(i=0;i<=count[leaf];i++)

{ temp=tree[leaf][i]; tree[leaf][i]= tree[x][i]; tree[x][i]= temp; }

}

for(i=leaf-1;i>=0;i--)count[i]=-1;

for(i=t,j=i-1;i>0;i--,j--) {

for(k=0;k<=count[i]/3;k++) { n1=tree[i][2*k]; n2=tree[i][(2*k)+1]; newnode=create_node(); count[j]++; tree[j][count[j]]=newnode; newnode->ele[0]=n1->ele[0]; newnode->child[0]=2*k; newnode->ele[1]=n2->ele[0]; newnode->child[1]=(2*k)+1; } if(count[i] != 1 && count[i]%2 == 0)

{



n2=tree[i][count[i]]; newnode->ele[2]=n2->ele[0]; newnode->child[2]=count[i];}

} }

int main(){ bptree bt; int choice,key; clrscr();while(1){ cout<<"\n\nMain Menu\n-----------------------\n 1.Insert\n 2.Search\n 3.DisplayTree\n 4.Exit\n\n Enter your choice:"; cin>>choice; switch(choice) { case 1:cout<<"\n Enter the element:";

cin>>key; bt.insert(key); break;

case 2:cout<<"Enter the key:"; cin>>key; bt.main_search(key); break;

case 3:bt.display_tree(); break;

case 4:return 0; default:cout<<"\nEnter valid choice"; } }}

11. Write a C++ program to store and retrieve student data from file using hashing. Use any collision resolution technique

#include<stdio.h>



#include<stdlib.h>#include<string.h>#include<conio.h>#include<fstream.h>#include<iostream.h>

//Record specification

class node{ public: char name[15],usn[15];

node *link;};

node *h[29] //Array of record pointers equal to size of hash keys - 29

void insert(){ char name[15], usn[15], buffer[50]; istream in; ofstream out; out.open("student.txt",ios::app); //opening student.txt in append mode if(!out) { cout<<"\nUnable to open the file in append mode"; getch(); return; }

cout<<"\nEnter the name = "; cin>>name; cout<<"\n Enter the usn = "; cin>>usn;

strcpy(buffer,name); //Packing the record onto the file using '|' as a delimiter strcat(buffer,"|"); strcat(buffer,usn); strcat(buffer,"\n"); // \n delimiter for the record out<<buffer; // appending the packed record onto the file out.close();}

//Insert record into the hash tablevoid hash_insert(char name1[], char usn1[], int hash_key){ node *p,*prev,*curr; p = new node; //dynamically allocate space using 'new' strcpy(p->name,name1); strcpy(p->usn,usn1); p->link=NULL; prev=NULL; curr=h[hash_key]; if(curr==NULL) //getting the hash pointer location Case: No collision {



h[hash_key]=p; return; } while(curr!=NULL) // Case : On collision - Insert at rear end { prev=curr; curr=curr->link; } prev->link=p;}

void retrive(){ fstream in; char name[15],usn[15]; int j,count; node *curr; in.open("student.txt",ios::in); // open the record file in input mode if(!in) { cout<<"\n Unable to open the file in input mode"; getch(); exit(0); } while(!in.eof()) { in.getline(name,15,'|'); //unpacking the record in.getline(usn,15,'\n'); count=0; for(j=0; j<strlen(usn); j++) //Calculate sum of ascii values of USN {

count=count+usn[j]; } count=count%29; //Hash Key = ASCII count% 29 hash_insert(name,usn,count); } cout<<"\n Enter the usn = "; cin>>usn; count=0; for(j=0; j<strlen(usn); j++) // Calculating Hash Key count=count+usn[j]; count=count%29; curr=h[count]; if(curr == NULL) { cout<<"\nRecord not found"; getch(); return; } do {

if(strcmp(curr->usn,usn)==0) //When the record is found, retrieve{



cout<<"\nRecord found : "<<curr->usn<<" "<<curr->name; getch(); return;}else{ curr=curr->link;}

}while(curr!=NULL); //Search till end of list

if(curr==NULL) //End of list reached with no record found { cout<<"\nRecord not found"; getch(); return; }}

void main(){ int choice; clrscr(); fstream out; out.open("student.txt",ios::out); if(!out) {

cout<<"\nUnable to open the file in out mode";getch();exit(0);

} for(;;) {

cout<<"\n1:insert\n 2: retrive \n3:exit \nEnter the choice - ";cin>>choice;switch(choice){ case 1: insert();

break; case 2: retrive();

break; case 3: exit(0); default: cout<<"\nInvalid option";}

}}

12. Write a C++ program to reclaim the free space resulting from the deletion of records using linked lists.

#include<stdio.h>



#include<conio.h> #include<stdlib.h> #include<string.h> #include<iostream.h> #include<fstream.h> #include<new.h>

class node{ public: char name[20];

char usn[20]; node *link;

};node *first=NULL;

void writeFile(){ node *p; char buffer[100]; fstream out; out.open("student.txt", ios::out); if(!out) { cout<<"\n Unable to open the file student.txt in out mode"; getch(); exit(0); } p=first; while(p!=NULL) { strcpy(buffer,p->name); strcat(buffer,"|"); strcat(buffer,p->usn); strcat(buffer,"\n"); out<<buffer; p=p->link; }}

void display(){ node *p; if(first==NULL) { cout<<"\nList is empty"; return; } p=first; while(p!=NULL) { cout<<"|"<<p->name<<" "<<p->usn<<"|"<<"->"; p=p->link;



}}

void Insert() //Insert the record at the rear end{ char name[20],usn[15]; node *p,*q; cout<<"\n Enter name = "; cin>>name; cout<<"\nEnter usn = "; cin>>usn; p=new node; strcpy(p->name,name); strcpy(p->usn,usn); p->link=NULL; if(first==NULL) {

first=p;writeFile();display(); //display the record on the screenreturn;

} for(q=first; q->link!=NULL; q=q->link) {

; } q->link=p; writeFile(); //writing the record to the file display(); //display the records to the screen.}

void Delete(){ char usn[15]; node *curr,*prev,*del; if(first==NULL) { printf("\nThe list is empty. Deletion is not possible"); return; } cout<<"\nEnter the usn to be deleted = "; cin>>usn; if(strcmp(first->usn,usn)==0) {

cout<<"\n Record deleted";del = first;delete del;first=first->link;writeFile();return;

} prev=NULL; curr=first; while( ( strcmp(curr->usn,usn) != 0 ) && curr!=NULL) {



prev=curr; curr=curr->link; } if(curr == NULL) { cout<<"\nThe student with usn "<<usn<<" is not present"; return; } prev->link = curr->link; writeFile(); display(); //display the records to the screen}

void main(){ int ch; clrscr(); for(;;) { cout<<"\n 1-Insert_rear \n 2-Delete_id \n 3-Exit \n Enter choice"; cin>>ch; switch(ch) {

case 1: Insert(); break;

case 2: Delete(); break;

case 3: exit(0); default: cout<<"\n Invalid option";

break; } }}

Appendix-I

A file structure is a combination of representations for the data in files and of operations for accessing the data.



Operations on file handling in C++

1.Class stream -In C++ ,we open a file by linking it to a stream. For obtaining a stream we have three types i) input - ifstream in: ii) output - ostream out: iii) input and output - fstream io:Once you create a stream, one way to associate it with a file is by using open( ) 2.Opening a file –The member function open ( ) is used to open a file open (filename, mode): filename- is a sting that holds the name of the file on disk Mode- is optional parameter with a combination of the following flags.•ios::in -open for reading only•ios::out -open for writing only•ios::app -append to end of file•ios::ate -set initial position at the end of a file•ios::binary - binary file•ios::trunc -delete contents of file if it exists.

Prototype for stream classes is shown below

void ifstream::open(const char *filename. ios::openmode mode=ios::in); void ofstream::open(const char *filename. ios::openmode mode=ios::out ios::trunc); void fstream::open(const char *filename. ios::openmode mode=ios::in ios::out);

This can be done using stream member function close ( )

4. Reading a file- there are several ways of reading a text from a file.but all of them have a common approach as followsopen the fileread the fileclose the file

5.Writing a file- writing to a text file can be accomplished with stream operators and it follows open a filewrite a fileclose a file

6. Seeking a position in a file- ifstream, has a pointer called the get pointer that points to the next element to be read. ofstream, has a pointer called the put pointer that points to the location where the next element has to be written. The stream classes support the following functions to manage the pointers:seekg( )-moves get pointer to specific locationseekg(offset,position)seekp( )- moves put pointer to a specific locationseekp(offset,position)

tellg( )-gives the current position of get pointer

tellp( )-gives the current position of put pointer



Where offset indicates the number of bytes the file pointer is moved from the location specified by position. Position will take the following constraints defined in the ios class

ios::beg offset count from the beginning of the streamios::cur offset counted from the current position of the streamios::end - offset counted from the end of the stream.

Appendix-II

I/O redirection and pipes in UNIXUsually, the output is displayed on the terminal but in some cases if the input of a file listing the program is needed as i/p to another program or if the o/p is to be stored in a file than displaying on terminal or if i/p to a terminal or if i/p to a program is taken from a file, than a common method called I/O redirection and pipes are used.Here Operating system switches from standard I/O and regular file I/O. there are three streams in UNIX which are given below

Standard input-the file representing input, usually connected to keyboard< file (redirects standard input to “file”)

Standard output-the file representing put, usually connected to> file (redirects standard output to “file”)

Standard error- the file representing error messages that emanate from command or shell, usually connected to display.

UNIX provides tools for redirecting the output of one program as input to other program. the mete character ‘” is used for this purpose.

Appendix-III



Program in C++ to display the contents of a fileLots do some reading and writing to see how these functions are used. The first simple file

processing program opens a file for input and reads it, char by char, sending each character to the screen after it is read from the file. This program includes the following steps:-1. Display a prompt for the name of the input.2. Read the user’s response from the keyboard into a variable called filename.3. Open the file for input.4. While these are still characters to be read from the input file,

i) Read a char from the file.ii) Write the char to the terminal screen.

5. Close the input file.

In C++ stream:-#include<iostream.h>main(){

Char ch;Fstream file;Char filename[20];

cout<<”Enter the name of the file:”<<flush; cin>>filename; file.open(filename,ios::in); while {

file>>ch; if(file.fail()) break; cout<<ch;

} file.close();}

Appendix-IV

Unix file system commands

Unix provides many commands for manipulating files.

Cat filenames:- Print the contents of the named text files.Tail filename:- Prints the last ten lines of the text file.Cp file1 file2:- Copy file1 to file2.Mv file1 file2:- Move(rename) file1 to file2.Rm filenames:- Remove(delete) the named files.Chmod mode filename:- Changes the protection mode on the named file.Ls:- List the contents of the directory.Mkdir name:- Create a directory with the given name.Rmdis name:- Remove the named directory

Appendix-V



Field Structures

A filed is the smallest logical meaningful unit of information in a file

There are many ways of adding structures to files to maintain the identity of the fields. Four of the most common methods follow:-

1. Force the fields into a predictable length.2. Begin each field with a length indicator.3. Place a delimiter at the end of each fields to separate it from the next fields.4. Use a “Keyword=Value” expression to identify each fields and its contents.5.

Fig (a)Ames Mary 123 Maple Stillwater OK74075Mason Alan 90 Eastgate Ada OK74820

<----10------><---10-----><--------10-----------><----------10---------><-------10------>

fig (b)04Ames04Mary09123 Maple10Stillwater020OK7407505Mason04Alan1190 Eastgate03Ada02OK74820

fig (c)Ames | Mary| 123 Maple | Stillwater | OK | 74075Mason | Alan | 90 Eastgate | Ada | OK | 74820

fig (d)last=Ames | first=Mary | address=123 Maple | city=Stillwater | state=OK | zip=74075last=Mason | first=Alan | address=90 eastgate | city=Ada | state=OK | zip=74820

Reading a Stream of Fields

istream & opreator >> (istream & stream, person &p){ //read delemeted fields from file char delim; stream.getline(p.lastname,30,'1'); if (strlen(p.lastname==0)) return stream; stream.getline(p.lastname,30,'1'); stream.getline(p.address,30,'1'); stream.getline(p.city,30,'1'); stream.getline(p.state,15,'1'); stream.getline(p.zipcode,10,'1');} The output of above program looks like this for delimited-field version

LastName 'Ames'FisrtName 'Mary'Address '123 Maple'

Appendix-VI



Record Structure

A Record can be defined as a set of fields that belong together when the file is viewed in terms of a higher level of organization. Like the notion of a filed, a record is another conceptual tool. Records do not necessarily exist in the logical notion included in the file's structure.

A record in a file represents a structured data objects. The C++ programming examples are focused on adding methods to classes to support using files to preserve the state of objects.

Following are some of the most often used methods for organizing the records of a file:

Method 1:- Make Records a Predictable Number of Bytes(Fixed-Length Records)A fixed-length record file is one in which each record contains the same number of bytes. Fixed

length records are frequently used as containers to hold variable number of variable fields. It is also possible to mix fixed & variable length field within a record.

Fig (a) Fixed-Length records with fixed-length fields

Ames Mary 123 Maple Stillwater OK74075 Mason Alan 90 Eastgate Ada OK74820

Fig (b) fixed length records with variable length fields

Ames: Mary:123 Maple:Stillwater:OK74075:<----------------unused space------------------------> Mason :Alan:90 Eastgate:Ada:OK74820:<----------------------unused space----------------------->

Method 2:- Make Records a Predictable Number of FieldsRather than specify that each record in a file contain some fixed number of bytes. We can specify

that it will contain a fixed number of fields. This is a good way to organize the records looking at

fig (c) six fields per record.

1 2 3 4 5 6Ames : Mary : 123 Maple : Stillwater : OK : 74075 :Mason : Alan : 90 : Eastgate : Ada : OK : 74820

Methods 3:- Begin each Record With a Length IndicatorWe can communicate the length of records by beginning each record with a field containing an

integer that indicates how many bytes there are in the rest of the record This is commonly used method for handling variable length records.

04Ames : Mary : 123 Maple : Stillwater : OK : 74075 :36 Mason : Alan : 90 Eastgate : Ada : OK | 74820

Method 4:-Use an Index to keep track of addressWe can use an index to keep a byte offset for each record in the originate file. The byte offsets

allow us to find the beginning of each successive record and compute the length of each record. We look up the portion of a record in the index then seek to the record in the data file.Fig (e) illustrate this two file mechanism

fig (e)



Data Files:Ames:Mary:123:Maple:stillwater:OK:74075:Mason:Alan:90: Eastgate:Ada:OK74820

Index file:

00 40

Method 5:-Place a Delimiter at the end of each Record

fig (f)

Ames:Mary:123Maple:Stillwater:OK:74075:#Mason:Alan:90 EastGate:Ada:OK74820

A Record Structure That uses a length indicator.Selection of a method for record organization depends on the nature of the data and on what you

need to do with it. We begin by looking at a record structure that uses a record-length at the beginning of the record. This approach let’s us preserve the variability’s in the length of records that is inherit in our stream file.

Writing the variable-length records to the fileImplementing variable length records is practically a matter of building on the program in

writstream.cpp, but it also involves addressing some new problems.

If we want to put a length indicator at the beginning of every record(before any other field) we must know the sum of lengths of the fields in each record before we can begin. Writing a record to the file, we need to accumulate the entire content of the record in a buffer before writing it out.

In what form should we write the record length field to the file? As a binary integer?The concepts of buffering are one we run into again and again as we work with files. In this case,

the buffer can simply be a character array into which we place the fields and field Delimiter as we collect them. A C++ function writeperson, written using the C string function, is found in the below program. This function creates a buffer; fills it with the delimited field values using strcat, the string concatenation function; calculates the length of the buffer using strlen; then writes the buffer length to the buffer to the output stream.

Const int MaxBuffersize=200;int WritePerson (ostream & stream, person & p){ char buffer [MaxBufferSIze]; //creates a buffer of fixed sizeStrcpy(buffer,p.lastName); Strcat(buffer,”|”);Strcat(buffer,p.FirstName); Strcat(buffer,”|”);Strcat(buffer,p.Address); Strcat(buffer,”|”);Strcat(buffer,p.city); Strcat(buffer,”|”);Strcat(buffer,p.state); Strcat(buffer,”|”);Strcat(buffer,p.zipcode); Strcat(buffer,”|”);short length=strlen(buffer);stream.write(&length, size of (length)); //write lengthstream.write(&buffer, length);}

Reading the variable -length records from the file



Given our file structure of variable -length records proceeded by record length fields, it is easy to write a program that reads through file, record by record displaying the fields from each of the records on the screen .The program must read the length of a record, move the characters of the record into a buffer, then break the record into fields .The code to read and break up the record is included into function read variable person in the following program fragment,In the read variable person (istream and stream, person and p){//read a variable sized record from stream and store it in p//short length;stream read(&length,size of(length));char *buffer=new char[length +1];strem.read(buffer,length);buffer[length]=0;istrem strbuff(buffer);strbuff>>p;return 1;}


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