How are tested challenge's codes ?

Question

Sololearn's environment strange behavior... poor learning :'(
https://code.sololearn.com/cobbwa2wj4iC/?ref=app

Answer 1

According to the C ( and C++ ) standard an undefined macro evaluates to 0 so "Try Again" is the correct output.

You can use the -Wundef and -Werror flags to make it an error though, but that would generate a different error than what gcc 10 generated. ( "SOLO" is not defined, evaluates to 0 )

It would be weird if undefined macros would be an error because then you wouldn't be able to conditionally compile certain parts of code.

It compiles correctly on https://godbolt.org/z/EW6v1E with gcc 10 compiler without error.

Just to prevent confusion, SOLO is assumed to be a macro here, NOT an identifier.

Sololearn uses gcc as the compiler too, btw.

Answer 2

MY fault ! Too much warnings enabled in my IDE ? ;)
I dont push my research far enough on Stackoverflow...

Answer 3

I only see, header file not included warning...

#if !SOLO means if not defined SOLO. (about macro).
It is different from if( ! SOLO), here it will error as "declare it before you use..."

(Correct me if am wrong..
@Dennis...)

Answer 4

Thanks to all for your comments !

Answer 5

Jayakrishna🇮🇳
Yea, that's correct.

I ignored the header file warning because of the comment.

Answer 6

Dennis thanks sir, for the feedback..