What does return 0 means and why does we need to use this?

Answer 1

The function has an "int" return datatype.... If you dont care about returns (but you're still forced to use return due to the return-type) you just return a random nuber like 0...

Answer 2

https://www.sololearn.com/discuss/220394/?ref=app
https://www.sololearn.com/discuss/235256/?ref=app

Answer 3

In every C program you have to use return return 0; (or return -1;, or whatever... ), because the main function signature requires it.
In a C++ program the statement is optional: the compiler automatically adds a return 0; if you don't explicitely return a value.

The return value is the exit code of your program, the shell (or any other application that ran it) can read and use it.
The 0 exit code is a widely accepted convention for 'OK the program execution was successfull'.

taken from https://cheeze.club/2gnw