Question

All applicants to our company must pass a simple quiz using C as part of early screening process.

It consists of a C source file that must be modified to provide the desired functionality. We clearly state that we will attempt to compile the file as-is, with no changes.

Almost all applicants user “strlen” but half of them do not include “string.h”, so it does not compile until I include it.

Are they just lazy or are there compilers that do not require you to include standard library files, such as “string.h”?

Answer 1

GCC will happily compile the following code as is:

main()
{
   printf("%u\n",strlen("Hello world"));
}

It will complain about incompatible implicit declaration of built-in function ‘printf’ and strlen(), but it will still produce an executable.

If you compile with -Werror it won’t compile.