C Program to Implement Call By Value using Functions

#include <stdio.h>
swap (int, int);
main()
{
    int a, b;
    printf("\nEnter value of a & b: ");
    scanf("%d %d", &a, &b);
    printf("\nBefore Swapping:\n");
    printf("\na = %d\n\nb = %d\n", a, b);
    swap(a, b);
    printf("\nAfter Swapping:\n");
    printf("\na = %d\n\nb = %d", a, b);    
}
swap (int a, int b)
{
    int temp;
    temp = a;
    a = b;
    b = temp;
}

 OUTPUT:

Enter value of a & b: 10 20

Before Swapping:

a = 10

b = 20

After Swapping:

a = 10

b = 20

You can Find Example program for Call-By-Reference here.