Binary Operators 重载

二元运算符有两个参数，下面是二元运算符的例子。 您经常使用二元运算符，如加（+）运算符，减法（ - ）运算符和除法（/）运算符。

以下示例说明了如何重载加号（+）运算符。 类似地，您可以重载减法（ - ）和除法（/）运算符。

#include <iostream>
using namespace std;
class Box {
   double length;      // Length of a box
   double breadth;     // Breadth of a box
   double height;      // Height of a box
   public:
   double getVolume(void) {
      return length * breadth * height;
   }
   void setLength( double len ) {
      length = len;
   }
   void setBreadth( double bre ) {
      breadth = bre;
   }
   void setHeight( double hei ) {
      height = hei;
   }
   // Overload + operator to add two Box objects.
   Box operator+(const Box& b) {
      Box box;
      box.length = this->length + b.length;
      box.breadth = this->breadth + b.breadth;
      box.height = this->height + b.height;
      return box;
   }
};
// Main function for the program
int main() {
   Box Box1;                // Declare Box1 of type Box
   Box Box2;                // Declare Box2 of type Box
   Box Box3;                // Declare Box3 of type Box
   double volume = 0.0;     // Store the volume of a box here
   // box 1 specification
   Box1.setLength(6.0); 
   Box1.setBreadth(7.0); 
   Box1.setHeight(5.0);
   // box 2 specification
   Box2.setLength(12.0); 
   Box2.setBreadth(13.0); 
   Box2.setHeight(10.0);
   // volume of box 1
   volume = Box1.getVolume();
   cout << "Volume of Box1 : " << volume <<endl;
   // volume of box 2
   volume = Box2.getVolume();
   cout << "Volume of Box2 : " << volume <<endl;
   // Add two object as follows:
   Box3 = Box1 + Box2;
   // volume of box 3
   volume = Box3.getVolume();
   cout << "Volume of Box3 : " << volume <<endl;
   return 0;
}

编译并执行上述代码时，会产生以下结果 -

Volume of Box1 : 210
Volume of Box2 : 1560
Volume of Box3 : 5400