Why we can not use void instead of int to a main function

Answer 1

Data type void for main function has been slowly deprecated, since main functions should return values to the system.

Answer 2

void main() or getch() are from old/outdated C/C++ implementations. You should not use them. You should use int main() and return a value to the operating system to indicate whether your program has exited normally.

getch() is function from conio.h which is MS-DOS library. It's not part of C/C++ standard library so you shouldn't use it. You can use getchar() instead.

Answer 3

can I use getch in c++?