Why can't i compile?

I get this linker error when trying to compile the attached code:

C:/MINGW/LIB//libmingw32.a(main.o)(.text+0x7f):main.c: undefined reference to `WinMain@16'

Whats wrong with it?

It's because you don't have a main function.

You need to have a WinMain function, if that isn't your current main cpp program, then change the file to a header file.

I can't have two files or more. It won't link them at all. I have no idea how to use multible files, even inside a project.

I get blank errors.