Why do we use int main here in solo learn rather than Void as a function?

Answer 1

The short answer, is because the C/C++ standard requires main() to return int . As you probably know, the return value from the main() function is used by the runtime library as the exit code for the process. Both Unix and Win32 support the concept of a (small) integer returned from a process after it has finished.
First thing that appeared when I searched your question. Taken from stackoverflow.

Answer 2

Get return value accordingly to programmer