预处理器和宏

Question

#include <stdio.h>
#define macro(n, a, i, m) m##a##i##n
#define MAIN macro(n, a, i, m)
int MAIN()
{

    printf("GeeksQuiz");

    return 0;
}

Hello people In this question the output is geeksquiz as it says that main is first replaced by macro then again replaced. Where does the actual replacement take place ? Isn't it just defining functions ? Thank you

Answer 1

This takes place in the fourth phase of translation (known as the preprocessing phase) by the compiler.

You can read up on " Phases of Translation "

If there was some other name of the function other than macro , would it have done the same or defined it as different functions

Yes. "macro" can be changed to some other name.

#define some_other_name(n, a, i, m) m##a##i##n
#define MAIN some_other_name(n, a, i, m)

How do we know when the main function is getting replaced. In cases ive seen that they are defined as separate functions, is it due to macro or MAIN ? ( Sorry new to C here )

Because MAIN is defined as a MACRO and the MACRO expansion is resulting in main .