#define 只是字符替換

可使用

#define MAX 100

int 
main (int argc, char *argv[])
{
    printf("MAX is %d\n", MAX);
    return 0;
}

 

gcc -E filename.c -o output.c

來看看

output.c:

# 1 "./def.c"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "./def.c"


int
main (int argc, char *argv[])
{
   printf("MAX is %d\n", 100);
   return 0;
}