C Program Swap Numbers in Cyclic Order Using Call by Reference

This program takes three integers from the user and swaps them in cyclic order using pointers.

To understand this example, you should have the knowledge of following C programming topics:

Three variables entered by the user are stored in variables a, b and c respectively.

Then, these variables are passed to the function cyclicSwap(). Instead of passing the actual variables, addresses of these variables are passed.

When these variables are swapped in cyclic order in the cyclicSwap() function, variables a, b and c in the main function are also automatically swapped.

Example: Program to Swap Elements Using Call by Reference

#include<stdio.h>
void cyclicSwap(int *a,int *b,int *c);

int main()
{
    int a, b, c;

    printf("Enter a, b and c respectively: ");
    scanf("%d %d %d",&a,&b,&c);

    printf("Value before swapping:\n");
    printf("a = %d \nb = %d \nc = %d\n",a,b,c);

    cyclicSwap(&a, &b, &c);

    printf("Value after swapping:\n");
    printf("a = %d \nb = %d \nc = %d",a, b, c);

    return 0;
}
void cyclicSwap(int *a,int *b,int *c)
{

    int temp;

    // swapping in cyclic order
    temp = *b;
    *b = *a;
    *a = *c;
    *c = temp;
}

Output

Enter a, b and c respectively: 1
2
3
Value before swapping:
a = 1 
b = 2 
c = 3
Value after swapping:
a = 3 
b = 1 
c = 2

Notice that we haven't returned any values from the cyclicSwap() function.