dslabrecord

8/2/2019 DSLabRecord

1/7

CS010 407: Data Structures Lab Record

ST. JOSEPH'S COLLEGE OF ENGINEERING AND TECHNOLOGY, PALAI

Department of Computer Science and Engineering

Lab Record

CS010 407: Data Structures

Program : B. Tech. Semester : IV

Session : 2012-13 Subject Code : CS010 407

Subject Name : Data Structures Credits : 2

Student Name : Mr/Ms XXXXX

Department of Computer Science and Engineering P a g e | 1


2/7


Index

EXPNO

AIM OF THE PROGRAMDATE OF

SUBMISSIONSIGNATURE

1 Implement Infix to postfix conversion using Array DD/MM/YY

2 DD/MM/YY

3 DD/MM/YY

Exp No: 01

Date : DD/MM/YY



3/7


AIM : Implement Infix to postfix conversion using Array

ALGORITHM :

SOURCE CODE:

/************************************************************* Filename: infix_to_postfix.c* Description: infix to postfix conversion using stack* Author:Sarju S* Date: 01-Dec-2011*************************************************************/#include#include#define MAX_EXPR_SIZE 100#define MAX_STACK_SIZE 100

typedef enum {eos,lparen, rparen, plus, minus, times, divide,mod,operand} precedence;char infixExpr[MAX_EXPR_SIZE],postfixExpr[MAX_EXPR_SIZE];

precedence stack[MAX_STACK_SIZE];int top=-1,infixCount=0,postfixCount=0;

void stackFull(){

fprintf(stderr, "Stack is full cannot add elements\n");exit(EXIT_FAILURE);

}

void stackEmpty(){

fprintf(stderr, "Stack is empty cannot delete elements\n");exit(EXIT_FAILURE);

}

void push(precedence item){/* add an element to stack */

if(top>=MAX_STACK_SIZE-1)stackFull();

top++;stack[top] = item;

}

precedence pop(){/*Delete top element from the stack*/

if(top==-1)stackEmpty();

return stack[top--];}

void printToken(precedence token){

/* to print the symbol corresponding to token*/switch(token) {

case 3 :postfixExpr[postfixCount]='+';



4/7


postfixCount++;break;

case 4 :postfixExpr[postfixCount]='-';postfixCount++;

break;case 5 :postfixExpr[postfixCount]='*';

postfixCount++;break;

case 6 :postfixExpr[postfixCount]='/';postfixCount++;break;

case 7 :postfixExpr[postfixCount]='%';postfixCount++;}

}

precedence getToken(char *symbol){ /* get the next token, symbol is the character representation,which is

returned, the token is represented by its enumerated value, which isreturned in the function name */

*symbol = infixExpr[infixCount];infixCount++;switch(*symbol) {

case '\0': return eos;case '(' : return lparen;case ')' : return rparen;case '+' : return plus;case '-' : return minus;case '/' : return divide;case '*' : return times;case '%' : return mod;default : return operand;}

}

int checkPriority(precedence token){switch(token) {

case plus :

case minus : return 4;case times :case divide : return 6;}

}

void infixToPostfix(){/* output posfix of expression */

char symbol;precedence token;top = 0;

stack[0]= eos;token = getToken(&symbol);while(token!=eos){

if(token == operand){



5/7


postfixExpr[postfixCount]=symbol;postfixCount++;

}

else if(token == rparen){/*unstack tokens until left paranthesis */

while(stack[top]!= lparen)printToken(pop());

pop(); /*remove left paranthesis */}else {/*remove and print symbols whose in-stack precedence is greater than or

equal to the current tokens incomming precedence */if(token!=1) /*Avoid Comparison of Left Paranthesis */while(checkPriority(stack[top])>= checkPriority(token))

printToken(pop());

push(token);}

token =getToken(&symbol);}while((token = pop())!=eos)

printToken(token);postfixExpr[postfixCount]='\0';

}

void main(){printf("\nEnter the INFIX expression:");scanf("%s",infixExpr);infixToPostfix(); /* Function Call*/

printf("\nThe POSTFIX expression:");printf("%s\n",postfixExpr);

}

INPUT :

a) a/b-c+d*e-a*cb) ((a/(b-c+d)))*(e-a)*c

OUTPUT:

sjcet@sjcet-laptop:~$ gcc infix_to_postfix.csjcet@sjcet-laptop:~$ ./a.out

Enter the INFIX expression:a/b-c+d*e-a*c

The POSTFIX expression:ab/c-de*+ac*-sjcet@sjcet-laptop:~$ ./a.out

Enter the INFIX expression:((a/(b-c+d)))*(e-a)*c

The POSTFIX expression:abc-d+/ea-*c*sjcet@sjcet-laptop:~$



6/7


RESULT: The above program is executed successfully and the output is verified.



7/7


Exp No: 02

Date : DD/MM/YY


dslabrecord

Documents