#include <stdio.h>

void swap1(int a, int b)
{
    int temp = a;

    a = b;
    b = temp;
}

void swap2(int *a, int *b)
{
    int *temp = a;

    a = b;
    b = temp;
}

void swap3(int *a, int *b)
{
    int temp = *a;

    *a = *b;
    *b = temp;
}

main()
{
    int a = 9, b = 4;

    printf("%d , %d\n", a, b);
    swap1(a, b);
    printf("%d , %d\n", a, b);
    swap2(&a, &b);
    printf("%d , %d\n", a, b);
    swap3(&a, &b);
    printf("%d , %d\n", a, b);

}