There is question that what should we use void main() or int main() ?
void main() { /* ... */ }
Or,
int main() { /* ... */ }
In both language C and C++, there is standard for it. You may refer the ISO C++ standard 3.6.1[2] or the ISO C standard 5.1.2.2.1
It is suggested to use,
int main() { /* ... */ }
In C, and
int main(int argc, char* argv[]) { /* ... */ }
There may be more versions of main() but they must all have return type int. The int returned by main() is a way for a program to return a value to “the system” that invokes it. On systems that doesn’t provide such a facility the return value is ignored, but that doesn’t make “void main()” legal C++ or legal C. Even if your compiler accepts “void main()” avoid it, or risk being considered ignorant by C and C++ programmers.
In C++, main() need not contain an explicit return statement. In that case, the value returned is 0, meaning successful execution. For example:
int main()
{
std::cout << "This program returns the integer value 0\n";
}
Note also that neither ISO C++ nor C99 allows you to leave the type out of a declaration. That is, in contrast to C89 and ARM C++ ,”int” is not assumed where a type is missing in a declaration. Consequently:
main() { /* ... */ }
is an error because the return type of main() is missing.
Refer – http://www.stroustrup.com/bs_faq2.html#void-main