57 lines
1.3 KiB
C++
57 lines
1.3 KiB
C++
// tmp2tmp.cpp -- template friends to a template class
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#include <iostream>
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using std::cout;
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using std::endl;
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// template prototypes
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template <typename T> void counts();
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template <typename T> void report(T &);
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// template class
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template <typename TT>
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class HasFriendT
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{
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private:
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TT item;
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static int ct;
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public:
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HasFriendT(const TT & i) : item(i) {ct++;}
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~HasFriendT() { ct--; }
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friend void counts<TT>();
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friend void report<>(HasFriendT<TT> &);
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};
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template <typename T>
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int HasFriendT<T>::ct = 0;
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// template friend functions definitions
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template <typename T>
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void counts()
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{
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cout << "template size: " << sizeof(HasFriendT<T>) << "; ";
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cout << "template counts(): " << HasFriendT<T>::ct << endl;
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}
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template <typename T>
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void report(T & hf)
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{
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cout << hf.item << endl;
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}
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int main()
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{
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counts<int>();
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HasFriendT<int> hfi1(10);
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HasFriendT<int> hfi2(20);
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HasFriendT<double> hfdb(10.5);
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report(hfi1); // generate report(HasFriendT<int> &)
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report(hfi2); // generate report(HasFriendT<int> &)
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report(hfdb); // generate report(HasFriendT<double> &)
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cout << "counts<int>() output:\n";
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counts<int>();
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cout << "counts<double>() output:\n";
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counts<double>();
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// std::cin.get();
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return 0;
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}
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