5_1.cpp

清华大学C++补充习题代码

//5_1.cpp
#include <iostream>
using namespace std;

class Width
{ 
public:
    Width() { ++count; }
    ~Width() { --count; }
    static int count;
};

int Width::count = 0;

int main()
{  Width w, x;
  cout << "现在是： " << w.count << " Widths.\n";
  { Width w, x, y, z;
    cout << "现在是： " << w.count << " Widths.\n";
  }
  cout << "现在是： " << w.count << " Widths.\n";
  Width y;
  cout << "现在是： " << w.count << " Widths.\n";
  return 0;
}
/*
程序运行结果为：
现在是： 2 Widths.
现在是： 6 Widths.
现在是： 2 Widths.
现在是： 3 Widths.
*/