Double Negation in C++

Question

I just came onto a project with a pretty huge code base.

I\'m mostly dealing with C++ and a lot of the code they write uses double negation for their boolean logic.

Answer 1

It side-steps a compiler warning. Try this:

int _tmain(int argc, _TCHAR* argv[])
{
    int foo = 5;
    bool bar = foo;
    bool baz = !!foo;
    return 0;
}

The 'bar' line generates a "forcing value to bool 'true' or 'false' (performance warning)" on MSVC++, but the 'baz' line sneaks through fine.