what does int mean in the main function in c++

Question

int main()

Answer 1

It means it returns an integer (a whole number)

That's why you have to write "return 0;" in the end.

Answer 2

Here function named sum is returning integer value so you have to use int.

Example :

int sum(int a,int b)
{
int c = a+b;
return c;
}

int main()
{
....
...
int d = sum(1,2);
printf("%d", d);
....
...
}