Day 6 Calling Function in C Programming language : Call by Reference
| Previous | Home | Next |
# Call by reference
We know that variables are stored somewhere in memory. So instead of passing the value of a variable to a function, we pass the address of argument then it is called Call By Reference. Inside the function, the address is used to access the actual argument.
Defining a Function: Consider the fuction swaping()
/* function definition to swap the values */
void swaping(int *a, int *b)
{
int c;
c = *a; /* save the value at address a */
*a = *b; /* put b into a */
*b = c; /* put c into b */
return;
}
Now, let us call the function swaping() bby passing values by reference as in the following example:
#include <stdio.h>
/* function declaration */
void swap(int *a, int *b);
int main ()
{
/* local variable definition */
int m = 100;
int n = 200;
printf("Before swap, value of a : %d\n", m );
printf("Before swap, value of b : %d\n", n );
/* calling a function to swap the values.
* &a indicates pointer to a ie. address of variable a and
* &b indicates pointer to b ie. address of variable b.
*/
swap(&m, &n);
printf("After swap, value of a : %d\n", m );
printf("After swap, value of b : %d\n", n );
return 0;
}
/* function definition to swap the values */
void swap(int *x, int *y)
{
int temp;
temp = *x; /* save the value at address x */
*x = *y; /* put y into x */
*y = temp; /* put temp into y */
return;
}
Output :
Before swap, value of a :100 Before swap, value of b :200 After swap, value of a :200 After swap, value of b :100
| Previous | Home | Next |