remove_if (not)

[monarch_dodra]

Basically, I have a string, and I want to remove all non alpha chars.

I'm trying to do it using algorithm, so I thought I'd do something like this:

iString.erase(
    std::remove_if(iString.begin(), iString.end(), &isalpha),
    iString.end()
);

The problem is that this removes all the alpha, the oposite of what I want to do.

I would use the algorithm std::copy_if or remove_if_not, but they don't exist. My other choice would be to pass std::not1(isalpha), but that doesn't work, since isalpha is not a function object.

I could write this:

struct isalphafuntor : public std::unary_function<int,bool>
{
    bool operator()(int iChar) const
    {
        return isalpha(iChar);
    }
};

But I would rather avoid it.

So my question is this one:

Can I, in a single line, pass the negated isalpha function to the remove if algorithm? or am I stuck with wrapping isalpha explicitly (or writting isnotalpha)?