#include <stdio.h>

void swap(int a, int b)
{
int temp = a;
a = b;
b = temp;
}

int main(void)
{
int a = 0;
int b = 0;
scanf("%d %d", &a, &b);
//swap전
printf("(swap before) a is %d\n", a);
printf("(swap before) b is %d\n", b);
swap(a,b);
//swap후
printf("(swap after) a is %d\n", a);
printf("(swap after) b is %d\n", b);
return 0;
}

이거 왜안됨? 왜안바뀌지 ㅠㅠ