list1014.cpp

teach yourself C++ in 21 days 第五版

// Listing 10.14 - Overload operator plus (+)

#include <iostream>

using namespace std;

class Counter
{
  public:
    Counter();
    Counter(int initialValue);
    ~Counter(){}
    int GetItsVal()const { return itsVal; }
    void SetItsVal(int x) {itsVal = x; }
    Counter operator+ (const Counter &);
  private:
    int itsVal;
};

Counter::Counter(int initialValue):
itsVal(initialValue)
{}

Counter::Counter():
itsVal(0)
{}

Counter Counter::operator+ (const Counter & rhs)
{
   return Counter(itsVal + rhs.GetItsVal());
}

int main()
{
   Counter varOne(2), varTwo(4), varThree;
   varThree = varOne + varTwo;
   cout << "varOne: " << varOne.GetItsVal()<< endl;
   cout << "varTwo: " << varTwo.GetItsVal() << endl;
   cout << "varThree: " << varThree.GetItsVal() << endl;

   return 0;
}