1 #include <stdio.h>
 2 
 3 #define MAX 5
 4 
 5 int main() {
 6   printf("MAX is %d\n", MAX);
 7 
 8   #undef MAX
 9 
10   #if defined(MAX)
11     printf("MAX id %d\n", MAX);
12   #else
13     printf("NOT DEFINED MAX!");
14   #endif
15 
16   return 0;
17 }