nofri.cpp

来自「本课程主要介绍面向对象程序设计的方法和c++语言的基本概念。以c++语言中的面向」· C++ 代码 · 共 51 行

// nofri.cpp
// limitation to overloaded + operator
#include <iostream>
using namespace std;
////////////////////////////////////////////////////////////////
class Distance                    //English Distance class
   {
   private:
      int feet;
      float inches;
   public:
      Distance() : feet(0), inches(0.0)  //constructor (no args)
         {  }                            //constructor (one arg)
      Distance(float fltfeet)     //convert float to Distance
         {                        //feet is integer part
         feet = static_cast<int>(fltfeet); 
	      inches = 12*(fltfeet-feet); //inches is what's left
         }
      Distance(int ft, float in)  //constructor (two args)
         { feet = ft; inches = in; }
      void showdist()             //display distance
         { cout << feet << "\'-" << inches << '\"'; }
      Distance operator + (Distance);
   };
//--------------------------------------------------------------
                                  //add this distance to d2
Distance Distance::operator + (Distance d2)   //return the sum
   {
   int f = feet + d2.feet;        //add the feet
   float i = inches + d2.inches;  //add the inches
   if(i >= 12.0)                  //if total exceeds 12.0,
      { i -= 12.0; f++;  }        //less 12 inches, plus 1 foot
   return Distance(f,i);          //return new Distance with sum
   }
////////////////////////////////////////////////////////////////
int main()
   {
   Distance d1 = 2.5;             //constructor converts
   Distance d2 = 1.25;            //float feet to Distance
   Distance d3;
   cout << "\nd1 = "; d1.showdist();
   cout << "\nd2 = "; d2.showdist();

   d3 = d1 + 10.0;                //distance + float: OK
   cout << "\nd3 = "; d3.showdist();
// d3 = 10.0 + d1;                //float + Distance: ERROR
// cout << "\nd3 = "; d3.showdist();
   cout << endl;
   return 0;
   }