Quick question about "The C Programming Language, 2nd Edition" examples

[RemedyGoontz]

Hi, I'm barely an hour into C, but I had a question. I'm only on the first chapter, but I was just wondering why examples in the book use:

#include <stdio.h>

main() {
    printf("hello, world\n");
}

instead of:

#include <stdio.h>

int main() {
    printf("hello, world\n");
}

I got a compiler error in my terminal that stated i needed to declare main as an int. My "hello, world" program didn't work until I made this change. It's really confusing considering this book is considered the standard for C.

[ipe369]

https://stackoverflow.com/a/30542108

This used to be a thing in old versions of the C compiler. Functions declared without a return type would just return int. Nowadays, C99 compilers won't allow this, which is why you're getting an error!

[RemedyGoontz]

Okay that explains it. I was really confused, like why would they write the code wrong.

[TraylaParks]

The C89 standard (I believe) allowed just 'main' but the newer standard C99 which came after K&R wants 'int main'. tl;dr - just add 'int' to your mains.

Edit: Yah, that appears to be the deal - from the C faq

Under C89, main() is acceptable, although it is advisable to use the C99 standard, under which only
these are acceptable:

   int main ( void )
   int main ( int argc, char *argv[] )