How does this “hello world!” program work?

Question

int main(void)
{ 
    return(\'yes\', *\"no\", **main, *********printf) (\"hello world!\\n\") *0; 
}

outputs hello world!, but how does it

Answer 1

Two things really:

1. Function pointers don't dereference the same as other pointers. *main == main
2. A comma separated list returns the value of the last element in the list

So if we simplify the pointers:

int main(void)
{ 
    return('yes', *"no", main, printf) ("hello world!\n") *0; 
}

And using the last element in the list as the value of the list

int main(void)
{ 
    return printf("hello world!\n") *0; 
}

printf returns the number of characters printed

int main(void)
{ 
    return 13 *0; 
}

And 13*0 is left as an exercise to the reader.