#include <stdio.h>

// This will swap local variables named x and y, but will not affect
// the values of variables in the main function
int swap_f (int x, int y) {
	int t;
	t = x;
	x = y;
	y = t;
	
	return 0;
}

// This will swap the values pointed to by x and y.
// The addresses themselves are not swapped.
int swap (int *x, int *y) {
	int t;
	t  = *x;
	*x = *y;
	*y = t;
	
	return 0;
}


int main () {
	int a = 3, b = 5;
	printf("Before swap a = %d, b = %d \n", a, b);
	swap_f(a, b);
	printf("After swap a = %d, b = %d \n", a, b);

	printf("Before pointer-based swap a = %d, b = %d \n", a, b);
	swap(&a,& b);
	printf("After pointer-based swap a = %d, b = %d \n", a, b);
    
    int *ap = (int*) malloc( sizeof(int) );
    int *bp = (int*) malloc( sizeof(int) );
    *ap = 3;
    *ab = 5;
	printf("Before pointer-based swap a = %d, b = %d \n", *ap, *bp);
	swap(ap,bp);
	printf("After pointer-based swap a = %d, b = %d \n", *ap, *bp);
    
    return 0;
}