#include <stdio.h>
#include <stdlib.h>
 
void echange(int* a , int* b){
	int c;
	c=*a;
	*a=*b;
	*b=c;
}

int main(void) {
	int x=14;
	int y=29;
	printf("avant : %d %d\n", x, y);
	echange(&x,&y);
	printf("apres : %d %d\n", x, y);
  	return 0;
}