please someone explain me the difference b/w using "return 0" and "getch()"?

Answer 1

both perform the same function but a different way to write it. Standard books generally uses return type instead of getch and it is better to use return as later on in complex problem using return is easier.

Answer 2

getch() is used to make sure when program output something the console will stay

while return is used to tell computer either program run successful or not