countedclass2.cpp

来自「很经典的书籍」· C++ 代码 · 共 27 行

//: C05:CountedClass2.cpp
// Erroneous attempt to count objects
#include <iostream>
using namespace std;

class Counted {
  static int count;
public:
  Counted() { ++count; }
  Counted(const Counted&) { ++count; }
  ~Counted() { --count; }
  static int getCount() { return count; }
};
int Counted::count = 0;

class CountedClass : public Counted {};
class CountedClass2 : public Counted {};

int main() {
  CountedClass a;
  cout << CountedClass::getCount() << endl;    // 1
  CountedClass b;
  cout << CountedClass::getCount() << endl;    // 2
  CountedClass2 c;
  cout << CountedClass2::getCount() << endl;   // 3 (Error)
} ///:~