摘要：#include <iostream>using namespace std;class A{public:A(double _data = 0.0) :data(_data){}A& operator =(const A& rhs){data = rhs.data;return *this;}friend A operator +(const A& lhs, const A& rhs);friend A operator -(const A& lhs, const A& rhs);friend A operator *(const 阅读全文