关系运算符重载

C++语言支持各种关系运算符重载(<,>,>=,<=,==)，他们可用于比较C++内置的数据类型。

支持重载任意一个关系运算符，重载后的关系运算符可以用于比较类的对象。

/***
overrealate.cpp
***/
#include<iostream>
using namespace std;class Distance
{private:int feet;int inches;public:Distance(){feet = 0;inches = 0;}Distance(int f,int i){feet = f;inches = i;}void displayDistance(){cout << "F: " << feet << " I: " << inches << endl; }Distance operator- (){feet = -feet;inches = -inches;return Distance(feet,inches);}bool operator <(const Distance& d){if(feet < d.feet){   return true;}if(feet == d.feet && inches < d.inches){return true;}return false;}
};int main()
{Distance D1(11,10), D2(5,11);if(D1 < D2){cout << "D1 is less than D2 " << endl;}else{cout << "D2 is less than D1" << endl; }return 0;
}

运行结果：

exbot@ubuntu:~/wangqinghe/C++/20190808$ ./overrelation

D2 is less than D1