2007 pearson education, inc. all rights reserved. structs as function arguments and results arrays...

2007 Pearson Education, Inc. All rights reserved.

Structs as Function Arguments and Results

Arrays– Pass by referance

Struts– the same way as the basic types in C - char, int, float

- passed as arguments

- returned as results

1


typedef struct Person{

int age;

char gnd;

float weight;

} PERSON;

2


the use of the members of a struct.

int adjustAge( int oldAge ){

if ( oldAge < 39 ) return( ++oldAge );

else return( oldAge );

/*return (oldAge<39) ? ++oldage : oldage;*/

}

void main(){

PERSON Jim;

:

Jim.age = adjustAge( Jim.age );

:

}

3


typedef struct Book{

int edition;

int pages;

double weight;

char type;

int WC; /*weight classification 1 heavy, 0 is not */

} BOOK;

Write a function tack an argument double to test the weight of a book and return 1 if the weight greater than 2 and 0 otherwise. The value to be assign to WC member.

4


int weightC(double w){

if(w > 2) return 1;

else return 0;

}

void main(){

BOOK myBok;

:

myBoK.wc = weightC(myBok.weight);

:

}

5

int weightC(double w){

return (w > 2)? 1 : 0;

}


ASS

Consider the student struct: add a new member name it GL /*Grades Later*/

Write a function tack a double to test the average of the student and return a later match the average to be assign to the new member

Test the function

6


The whole of a struct is returned by a function

PERSON get_details() {

PERSON temp;

printf("Please enter Age, Gender and Weight (Kg): ");

scanf("%d %c%f", &temp.age, &temp.gnd, &temp.weight );

return temp;

}

void main(){

PERSON Jim, Mary, Sid;

:

Jim = get_details();

:

}

7


Write a function allow the user to input the details of a BOOK and return it back


int edition;

int pages;

double weight;

char type;

} BOOK;

8


BOOK GetBook(){

BOOK tmp;

printf(“\nEnter the BOOK information:”);

printf(“ [edition, pages, weight, and type]”);

scanf(“%d%d%f%c”, &tmp.edition, &tmp.pages. &tmp.weight. &tmp.type);

retrun tmp;

}

void main(){

BOOK myBook;

:

myBook = GetBook();

:

}

9


ASS

Write a function allow the user to input the details of a STUDENTand return it back

Test the function

10


Passing a struct as a function argument

void show_details( PERSON who ){

printf( "Person's age was: %d\n", who.age );

printf( " Gender was: %c\n", who.gnd );

/* Kg -> lb */

who.weight = who.weight * 2.2;

printf( " weight (lb) was: %5.1f\n", who.weight );

}

void main(){

PERSON Jim, Mary, Sid;

:

Jim = get_details();

:

show_details(Jim);

}

11


Write a function tack a BOOK and print the content out

12


void PrintBook( const BOOK b){

printf(“The BOOK information:\n”);

printf(“\n\tedition: %d\n\tpages: %d”, b.edition, b.pages);

printf(“\n\tweight: %f \n\ttype: %c”, b.weight, b.type);

}

void main(){

BOOK myBook = {2, 120, 2.5, ‘A’};

:

PrintBook(myBook);

:

}

13


ASS

Write a function tack a STUDENT and print the content out

Test the function

14


Arrays of structs

to store the same package of information for a number of different entities

typedef struct Person{

int age;

char gnd;

float weight;

} PERSON;

15


Arrays of structs

PERSON employee[12];

We have an array of 12 elements each of which is a structure with 3 members. We can access any member of any element,

employee[9].age = 45;

Also we can treat each element as a whole structshow_details(employee[5]);

employee[3] = get_details();

16


Consider the following struct BOOK, Create an array of three BOOK s


int edition;

double weight;

char type;

} BOOK;

17


BOOK academic[3];

BOOK academic[3] = {

{1,2.5,’a’},

{2,3.5,’n’},

{2,1.5,’a’}

};

Read in the information of the second

18


academic[1] = GetBook();

Printout the information of the first

19


PrintBook(academic[0]);

Printout the content of the array

20


int i;

for(i=0; i<3; i++)

PrintBook(academic[i]);

21


ASS

1. Create an array of four STUDNTs with initial values

2. – Create another array of five STUDNTs

– Read in the information of the whole student

– Printout the content

– Assign the second the information of the second of the array created at 1

– Printout the information of the second

22


Structs Containing Arrays

typedef struct{

int age;

char gnd;

float weight;

char name[20];

} HUMAN;

HUMAN ahm = { 45, ‘M’, 95.1, “Ahmad Ali”};HUMAN ahm = { 45, ‘M’, 95.1, {‘A’, ‘h’, ‘m’, ‘a’, ‘d’, ‘ ‘, ‘A’, ‘l’, ‘i’, ‘\0’}};

23


char initial = ahm.name[0];

putchar(initial);

Printout the 3rd char of ahm’s name

24


char third = ahm.name[2];

printf(“%c”, third); /*putchar(third)*/

allow the user to input the 6th char of ahm’s name

25


scanf(“%c”, &ahm.name[5]);

print the name char by char

26


int i;

for(i=0; i<20; i++)

putchar(ahm.name[i]);

i=0;

while( ahm.name[i] != ‘\0’)

putchar(ahm.name[i++]);

Print out the name at once

27


printf(“%s\n”, ahm.name);

puts(ahm.name);

allow the user to input the ahm’s name

28


scanf(“%s”, ahm.name);

gets(ahm.name);

Which is better?

29



int edition;

double weight;

char type;

} BOOK;

Rewrite the BOOK with a new member title

30



int edition;

double weight;

char type;

char title[30];

} BOOK;

Create a variable of book with initial values

31


BOOK myBook = {1,2.5,’a’, “C programming” }

change the title to “c how to program”

32


gets(myBook.title);

scanf(“%s”, myBook.title);

33


ASS

Create a Time struct with classification member (“PM”, “AM”)

Write a function to print out the content of the Time

Create a STUDENT struct with a name member up to 30 char

Write two functions to read the information of a student and the second to print out the information.

34


HUMAN client[2] = {

35, ‘M’, 95.1, “Ahmad Ali”,

25, ‘F’, 50.9, "Salma Zakarea”

};

printf( "%s\n", client[1].name );

printf( "%c\n", client[1].name[0] );

35


HUMAN client[2] = {

35, ‘M’, 95.1, “Ahmad Ali”,

25, ‘F’, 50.9, "Salma Zakarea”

};

HUMAN temp;

Assign the values of first client to temptypedef struct{

int age;

char gnd;

float weight;

char name[20];

} HUMAN;

36


temp = client[0];

temp.age = client[0].age;

temp.gnd = client[0].gnd;

Temp.weight = client[0].weight;

strcpy(temp.name, client[0].name);

37

2007 pearson education, inc. all rights reserved. structs as function arguments and results arrays...

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