C++学习笔记之deepcopy

#include 
  
class Tricycle
{
public:
    Tricycle();                     // default constructor
    Tricycle(const Tricycle&);      // copy constructor
    ~Tricycle();                    // destructor
    int getSpeed() const { return *speed; }
    void setSpeed(int newSpeed) { *speed = newSpeed; }
    void pedal();
    void brake();
  
private:
    int *speed;
};
  
Tricycle::Tricycle()
{
    speed = new int;
    *speed = 5;
}
  
Tricycle::Tricycle(const Tricycle& rhs)
{
    speed = new int;
    *speed = rhs.getSpeed();
}
  
Tricycle::~Tricycle()
{
    delete speed;
    speed = NULL;
}

void Tricycle::pedal()
{
    setSpeed(*speed + 1);
    std::cout << "\nPedaling " << getSpeed() << " mph\n";
}
void Tricycle::brake()
{ 
    setSpeed(*speed - 1);
    std::cout << "\nPedaling " << getSpeed() << " mph\n";
}
  
int main()
{
    std::cout << "Creating trike named wichita ...";
    Tricycle wichita;
    wichita.pedal();
    std::cout << "Creating trike named dallas ...\n";
    Tricycle dallas(wichita);
    std::cout << "wichita's speed: " << wichita.getSpeed() << "\n";
    std::cout << "dallas's speed: " << dallas.getSpeed() << "\n";
    std::cout << "setting wichita to 10 ...\n";
    wichita.setSpeed(10);
    std::cout << "wichita's speed: " << wichita.getSpeed() << "\n";
    std::cout << "dallas's speed: " << dallas.getSpeed() << "\n";
    dallas.setSpeed(9);
    std::cout << "wichita's speed: " << wichita.getSpeed() << "\n";
    std::cout << "dallas's speed: " << dallas.getSpeed() << "\n";
    return 0;
}

可见，deepcopy的对象和原对象是指向不同的堆内存的。