c语言预编译 ifdef,C语言：#if #ifdef和#ifndef的综合应用

C语言#if #ifdef和#ifndef的综合应用代码如下：

程序源代码：

#include "stdio.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\n",MAXIMUM(a,b));

#else

printf("\40: The lower one is %d\n",MINIMUM(a,b));

#endif

#ifndef MIN

printf("\40: The lower one is %d\n",MINIMUM(a,b));

#else

printf("\40: The larger one is %d\n",MAXIMUM(a,b));

#endif

#undef MAX

#ifdef MAX

printf("\40: The larger one is %d\n",MAXIMUM(a,b));

#else

printf("\40: The lower one is %d\n",MINIMUM(a,b));

#endif

#define MIN

#ifndef MIN

printf("\40: The lower one is %d\n",MINIMUM(a,b));

#else

printf("\40: The larger one is %d\n",MAXIMUM(a,b));

#endif

}