标签：rda xls gcj w3c bka border ada namespace 1.5
| #include <iostream> using namespace std; class AnotherPoint { private: double _ax; double _ay; public: //explicit AnotherPoint(double x=0,double y=0):_ax(x),_ay(y) { cout<<"AnotherPoint(int,int)"<<endl; } friend std::ostream & operator << (std::ostream & os,const AnotherPoint &rhs); friend class Point; }; std::ostream & operator << (std::ostream & os,const AnotherPoint & rhs) { os<<"("<<rhs._ax<<","<<rhs._ay<<")"; return os; } class Point { private: int _x; int _y; public: //explicit Point(int x=0,int y=0):_x(x),_y(y) { cout<<"Point(int,int)"<<endl; } //explicit Point(AnotherPoint & a):_x(a._ax),_y(a._ay) { cout<<"Point(AnotherPoint & a)"<<endl; } //point& operator=(const anotherPoint& rhs); // 赋值运算符只能两个相同类型的类对象之间 friend std::ostream & operator << (std::ostream & os,const Point & rhs); }; std::ostream & operator << (std::ostream & os,const Point & rhs) { os<<"("<<rhs._x<<","<<rhs._y<<")"; return os; } | //由其它类型向自定义类型进行转换，都是通过构造函数来完成的 //隐式转换 //explicit可以禁止隐式转换 int main(void) { Point p1; cout<<5<<"转换成："; p1=5; //类型不同，所以构造函数转换 //如果有operator=这就就报错了 cout<<" p1 = "<<p1<<endl<<endl; double d1=1.5; cout<<d1<<"转换成："; p1=d1; cout<<" p1 = "<<p1<<endl<<endl; AnotherPoint p2(12.34,56.78); cout<<" p2 = "<<p2<<endl; cout<<"将p2转换成p1"<<endl; p1=p2; //两个都是类类型，所以直接赋值构造函数 cout<<" p1 = "<<p1<<endl<<endl; return 0; }  |
| #include <iostream> using namespace std; class AnotherPoint { private: double _ax; double _ay; public: AnotherPoint(double x=0,double y=0):_ax(x),_ay(y) { cout<<"AnotherPoint(double,double)"<<endl; } friend ostream & operator << (ostream & os,const AnotherPoint & rhs); }; class Point { private: int _x; int _y; public: Point(int x=0,int y=0):_x(x),_y(y) { cout<<"Point(int,int)"<<endl; } //类型转换函数 operator int() { return _x; } operator double() { return _x*_y; } operator AnotherPoint() { return AnotherPoint(_x,_y); // 这里直接返回类类型对象，所以不能单单AnotherPoint类前向声明，必须给出完整定义 } friend ostream & operator << (ostream &os,const Point & rhs); }; | ostream& operator << (ostream& os,const AnotherPoint & rhs) { os<<"("<<rhs._ax<<","<<rhs._ay<<")"; return os; } ostream& operator << (ostream& os,const Point & rhs) { os<<"("<<rhs._x<<","<<rhs._y<<")"; return os; } int main() { Point p(4,5); int x=p; cout<<"x = "<<x<<endl; double y=p; cout<<"y = "<<y<<endl; AnotherPoint p1; cout<<"p1 = "<<p1<<endl; p1=p; cout<<"p1 = "<<p1<<endl; return 0; }  |
标签：rda xls gcj w3c bka border ada namespace 1.5
原文地址：https://www.cnblogs.com/meihao1203/p/8915658.html
