what is the work of retun 0; ?

Question

why this statment is used in this program
what is the basic need of this statement
what is the statement

Answer 1

I'm assuming that you are referring to main function. when returning 0 it gives OS a signal that your program exits successfully(no error occurred). value other than 0 indicating that error occurred.

return 0 statement is optional, since you don't return value from main to other functions(no functions would call main function since the program starts from main function)