serika00

c9.h#include class Observer;class Subject {public: virtual void mregister(Observer* observer) = 0; virtual void remove(Observer* observer) = 0; virtual void notify() = 0;

c10.h#include class Beverage {public: virtual std::string getDescription() = 0; virtual double cost() = 0;};class Soy: public Beverage {private: Beverage* beverage; // 把

c11.h#include "c11.h"#include int main() { printf("singleton:\n"); Singleton* s1 = Singleton::getInstance(); printf("%d\n", s1->tag); s1->tag++; Singleton& s