>[info]#if #ifdef和#ifndef的综合应用。 ~~~C #include <stdio.h> #define MAX #define MAXIMUM(x,y) (x>y)?x:y #define MINIMUM(x,y) (x<y)?x:y int main() { int a=10,b=20; #ifdef MAX printf("更大的数字是%d\n", MAXIMUM(a,b)); #else printf("更小的数字是%d\n", MINIMUM(a,b)); #endif #ifndef MIN printf("更小的数字是%d\n", MINIMUM(a,b)); #else printf("更大的数字是%d\n", MAXIMUM(a,b)); #endif #undef MAX #ifdef MAX printf("更大的数字是 %d\n",MAXIMUM(a,b)); #else printf("更小的数字是 %d\n",MINIMUM(a,b)); #endif #define MIN #ifndef MIN printf("更小的数字是 %d\n",MINIMUM(a,b)); #else printf("更大的数字是 %d\n",MAXIMUM(a,b)); #endif return 0; } ~~~