Could you please explain the error?

Question

https://code.sololearn.com/c3HFEaRSuVIP/?ref=app

Answer 1

It's not error it's a warning
As main function always returns something to the system
So function main should have return type as int and void.
Even though main does not return anything then return type in int main is ignored
If you use void with main some compiler compiles with warning.

Answer 2

For some reason your code had illegal hidden characters/spaces

Works fine after I removed the spaces and used tabs
https://code.sololearn.com/cTak0j8TCXkw/?ref=app

Answer 3

use int main instead void main

Answer 4

Explain it, plz. Why int? Why? Why?