『新･明解Ｃ言語 入門編 第２版』演習問題解答例　８ー３

// Ex0803.c

#include <stdio.h>
#define swap(type, a, b) do{ type t = a; a = b; b = t; }while(0)

int main(void)
{
    int x, y;

    printf("整数を入力せよ：");
    scanf("%d", &x);

    printf("整数を入力せよ：");
    scanf("%d", &y);
    
    printf("交換前　x=%d y=%d\n", x, y);

    swap(int, x, y);

    printf("交換後　x=%d y=%d\n", x, y);

    return 0;
}