function object adapter

自己输入一遍代码，总是胜过仅仅阅读。

template <typename InputIterator, typename Predicate>
InputIterator Find_if(InputIterator& first, InputIterator& end, Predicate pred)
{
    while( first != end && !pred (*first))
        ++ first;
    return first;

}

template <typename Arg, typename Result>
struct unary_function{
    typedef Arg argument_type;
    typedef Result result_type;
};

template <typename Adapertable>
class negate_unary
{
    public:
    typedef typename Adapertable::argument_type Arg;
    typedef typename Adapertable::result_type   Result;
   
    negate_unary(const Adapertable& ad):pred(ad){}

    bool operator()(const Arg& ag) const{
   
        return !pred(ag);

    }  
    private:
    Adapertable pred;
};