摘要： #include<iostream>#include<string>using namespace std;class Sales_item;//前置申明,让Test识别Sales_itemclass Test{public: void GetName(Sales_item &item); std::string TestName;};class Sales_item{ friend void Test::GetName(Sales_item &item); //freind class Test;的话Test任何方法都能访问public: Sales_ 阅读全文