list1010.cpp

来自「teach yourself C++ in 21 days 第五版」· C++ 代码 · 共 47 行

// Listing 10.9
// operator++ returns a temporary object

#include <iostream>

using namespace std;

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

  private:
    int itsVal;
};

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

Counter Counter::operator++()
{
   ++itsVal;
   Counter temp;
   temp.SetItsVal(itsVal);
   return temp;
}

int main()
{
   Counter i;
   cout << "The value of i is " << i.GetItsVal() << endl;
   i.Increment();
   cout << "The value of i is " << i.GetItsVal() << endl;
   ++i;
   cout << "The value of i is " << i.GetItsVal() << endl;
   Counter a = ++i;
   cout << "The value of a: " << a.GetItsVal();
   cout << " and i: " << i.GetItsVal() << endl;
   return 0;
}