常用单例模式

class Singleton
{

public:
    static Singleton& getInstance();

private:
    Singleton(){}
    Singleton(const Singleton&) = delete;  //明确拒绝
    Singleton& operator=(const Singleton&) = delete; //明确拒绝
};

Singleton& Singleton::getInstance()
{
    static Singleton singleton;
    return singleton;
}