定义模板参数的迭代器类型

Question

In function below, how to tell the compiler that Iterator is the iterator of Cont ?

template<typename Cont, typename Pred>
Iterator<Cont> find_if(const Cont &c, Pred p)
{
    return std::find_if(std::begin(c), std::end(c), p);
}

Answer 1

template<typename Cont, typename Pred>
auto find_if(const Cont &c, Pred p)
-> decltype(std::begin(c)) // HERE
{
    return std::find_if(std::begin(c), std::end(c), p);
}

Or since version C++14:

template<typename Cont, typename Pred>
auto find_if(const Cont &c, Pred p) //All you need is auto
{
    return std::find_if(std::begin(c), std::end(c), p);
}