functionstaticsingleton.cpp

C语言数值算法程序大全（第二版）,课本文件

//: C10:FunctionStaticSingleton.cpp
// From "Thinking in C++, 2nd Edition, Volume 2"
// by Bruce Eckel & Chuck Allison, (c) 2003 MindView, Inc.
// Available at www.BruceEckel.com.
class Singleton1 {
  Singleton1() {}
public:
  static Singleton1& ref() {
    static Singleton1 single;
    return single;
  }
};

class Singleton2 {
  Singleton1& s1;
  Singleton2(Singleton1& s) : s1(s) {}
public:
  static Singleton2& ref() {
    static Singleton2 single(Singleton1::ref());
    return single;
  }
  Singleton1& f() { return s1; }
};

int main() {
  Singleton1& s1 = Singleton2::ref().f();
} ///:~