#include <stdio.h>
void HoanVi(int *a, int *b){
int c = *a;
*a = *b;
*b = c;
printf("\nTrong ham hoan vi: a = %d, b = %d ", *a, *b);
}
void main(){
int x = 2, y=6;
printf("\nTruoc: x = %d, y = %d ", x, y);
HoanVi(&x, &y);
printf("\nSau: x = %d, y = %d ", x, y);
}