call by reference swap program

Q. what is calling by reference? How it is different from call by value? Write a C function to swap two given numbers using call by reference mechanism.

Ans:

When an argument is passed by reference, the caller actually allows the called function to modify the original variable's value.

• Sends the address of a variable to the called function.
• Use the address operator(&) in the parameter of the called function.
• Anytime we refer to the parameter, therefore we actually referring to the original variable.
• If the data is manipulated and changed in the called function, the original data in the function are changed.

#include<stdio.h>

#include<conio.h>

void swaping(int *x, int *y);

int main()

{

 int n1,n2;

 printf("Enter first number (n1) : ");

 scanf("%d",&n1);

 printf("Enter second number (n2) : "); 

 scanf("%d",&n2);

 printf("\nBefore swapping values:"); 

 printf("\n\tn1=%d \n\tn2=%d",n1,n2);

 swaping(&n1,&n2);

 printf("\nAfter swapping values:");

 printf("\n\tn1=%d \n\tn2=%d",n1,n2);

 getch();

 return 0;

}

void swaping(int *x, int *y)

{

  int z;

  z=*x;

  *x=*y;

  *y=z;

}

Output: