std::vector<int> foo;

foo.push_back(0);
foo.push_back(1);
foo.push_back(2);
foo.push_back(3);
foo.push_back(4);

struct is_even
{
    bool operator()(int n)
    {
        return n % 2;
    }
};

std::vector<int>::iterator first_odd_number = std::find(foo.begin(), foo.begin() + 2, is_even);