#include <stdio.h>

void  swap( int *a, int *b );

int  main(void)
{
    int  a, b;

    a = 3;
    b = 5;
    swap( &a, &b );

    printf( "a = %d, b = %d\n", a, b );
    return  0;
}

void  swap( int *a, int *b )
{
    int c;

    c = *a; 
    *a = *b;
    *b = c;
}