c语言中的#ifdef和#ifndef

#include "stdio.h"
#include "conio.h"
#define MAX
#define MAXIMUM(x,y) (x>y)?x:y
#define MINIMUM(x,y) (x>y)?y:x
void main()
{
int a=10,b=20;
#ifdef MAX
printf("40: The larger one is %d ",MAXIMUM(a,b));
#else
printf("40: The lower one is %d ",MINIMUM(a,b));
#endif
#ifndef MIN
printf("40: The lower one is %d ",MINIMUM(a,b));
#else
printf("40: The larger one is %d ",MAXIMUM(a,b));
#endif
#undef MAX
#ifdef MAX
printf("40: The larger one is %d ",MAXIMUM(a,b));
#else
printf("40: The lower one is %d ",MINIMUM(a,b));
#endif
#define MIN
#ifndef MIN
printf("40: The lower one is %d ",MINIMUM(a,b));
#else
printf("40: The larger one is %d ",MAXIMUM(a,b));
#endif
getch();
}

原文地址:https://www.cnblogs.com/zhaoheng/p/4322214.html