what is the function of return

Question

When I entered 200 in place of 0 it did nothing so what's it's function

Answer 1

return will set the value of the return to the variable that called it. for example, let's say we have this:
int i = setITo15 ();
then in an integer function setITo15 we have this declaration:
into setITo15 ()
{return 15;}
when this function finishes the varable that called it, i, will be set to 15. if you're referring to return 0 I'm int main it simply returns 0 once the program reaches the end of its code, essentially saying that I did everything I was told to do. of the program stopped prematurely it would return a different code like -156725 or something like that. in this case it's just a difference between executing the program completely or not