gistfile1.cpp

#include <iostream>

template<class T>
class Out
{
private:
	T& mValue;

public:
	explicit Out(T& aValue)
		: mValue(aValue)
	{}

	operator T&() const
	{
		return mValue;
	}

	template<class U>
	Out<T>& operator=(const U& aValue)
	{
		mValue = aValue;
		return *this;
	}
};

template<class T>
class Out<T*>
{
private:
	T* mValue;

public:
	explicit Out(T* aValue)
		: mValue(aValue)
	{}

	operator T*() const
	{
		return mValue;
	}
};

template<class T>
Out<T> make_out(T& aValue)
{
	return Out<T>(aValue);
}

template<class T>
Out<T*> make_out(T* aValue)
{
	return Out<T*>(aValue);
}

void funcA(int* arg)
{
	*arg = 10;
}

void funcB(Out<int*> arg)
{
	*arg = 20;
}

void funcC(int& arg)
{
	arg = 30;
}

void funcD(Out<int>& arg)
{
	arg = 40;
}

int main()
{
	int x;
	funcA(make_out(&x));
	std::cout << x << std::endl;
	funcB(make_out(&x));
	std::cout << x << std::endl;
	funcC(make_out(x));
	std::cout << x << std::endl;
	funcD(make_out(x));
	std::cout << x << std::endl;
	return 0;
}