for_each function and operator()

Hello everyone,


I can not find related information in MSDN, so I want to confirm here, that,

the implementation of for_each is something like,

Code:

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template <class A, class B> B for_each (A begin, A end, B Func)
{
    while (begin != end) Func(*begin++);
    return Func;
}

---

So, operator(*A) of class Func will be invoked? Right?


thanks in advance,
George

Quote:

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the implementation of for_each is something like

---

The C++ Standard declares std::for_each() as:

Code:

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template<class InputIterator, class Function>
Function for_each(InputIterator first, InputIterator last, Function f);

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The MinGW port of g++ 3.4.5 has an implementation that amounts to:

Code:

---

template<class InputIterator, class Function>
Function for_each(InputIterator first, InputIterator last, Function f)
{
    for (; first != last; ++first)
    {
        f(*first);
    }
    return f;
}

---

Quote:

---

So, operator(*A) of class Func will be invoked? Right?

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Function::operator(InputIterator::value_type) is the overloaded operator that will be invoked.

Quote:

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So, operator(*A) of class Func will be invoked? Right?

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Actually, operator()(typename std::iterator_traits<A>::value_type) will be invoked.

I seems to me that Func doesn't necessarily have to be a function object but might be a simple function with a suitable prototype.

Quote:

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I seems to me that Func doesn't necessarily have to be a function object but might be a simple function with a suitable prototype.

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Yes, that is true.