or is not valid C++ : why does this code compile?

Question

Here is a very simple C++ application I made with QtCreator :

int main(int argc, char *argv[])
{
    int a = 1;
    int b = 2;

    if (a < 1 or b > 3)         


        

Answer 1

iso646.h defines a number of operator alternatives - it's part of the C++ standard.