模板类的非模板友元函数

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/*********************************/
/*   1.模板类的非模板友元函数
*
/*********************************/
#include <iostream>
using std::cout;
using std::endl;
template <typename T>
class HasFriend{
    private:
        T item;
        static int ct;
    public :
        HasFriend(const T&i):item(i){ct++;}
        ~HasFriend(){ct--;}
        friend void counts();
        friend void reports(HasFriend<T> &);//不是模板函数，只是使用了一个模板做参数，
//        意味必需要使用友元定义显示具体化
//        void report(HasFriend<short> &){...};
//        void report(HasFriend<double> &){...};
};
template <typename T>
int HasFriend<T>::ct = 0;
void counts()
{
    cout<<"int count:"<<HasFriend<int>::ct<<";"<<endl;
    cout<<"double count:"<<HasFriend<double>::ct<<";"<<endl;
}
void reports(HasFriend<int> &hf)
{
    cout<<"HasFriend<int>: "<<hf.item<<endl;
}
void reports(HasFriend<double> &hf)
{
    cout<<"HasFriend<double>: "<<hf.item<<endl;
}
int main()
{
    cout<<"No objects declared:"<<endl;
    counts();
    HasFriend<int> hfi1(10);
    cout<<"After hfi1 declared:"<<endl;
    counts();
    HasFriend<int> hfi2(20);
    cout<<"After hfi2 declared:"<<endl;
    counts();
    HasFriend<double> hfib(10.8);
    cout<<"After hfib declared:"<<endl;
    counts();
    reports(hfi1);
    reports(hfi2);
    reports(hfib);
    return 0;
}
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