swap 매크로

#include<stdio.h>

#define SWAP(x,y,t) ((t)=(x),(x)=(y),(y)=(t))

void main()

{

int a = 3, b = 5,t;

printf("%d %d\n", a, b);

SWAP(a, b, t);

printf("%d %d\n", a, b);

}