实验一

实验任务2：

#include<iostream>
using std::cout;
using std::endl;

class Point
{
    public:
        Point(int x0=0, int y0=0);
        Point(const Point&p);
        ~Point()=default;
        
        int get_x() const { return x; }
        int get_y() const { return y; }
        void show() const;
    
    private:
        int x,y;
};

Point::Point(int x0, int y0): x{x0},y{y0}
{
    cout << "copy constructor called." << endl;
}

Point::Point(const Point& p): x{p.x}, y{p.y} 
{
    cout << "copy constructor called." << endl;
}

void Point::show() const
{
    cout<<"("<< x <<","<< y <<")"<<endl;
}

int main()
{
    Point p1(3,9);
    p1.show();
    
    Point p2=p1;
    p2.show();
    
    Point p3(p2);
    p1.show();
    
    cout<< p3.get_x() <<endl;
}

实验任务3：

#include <iostream>
#include <iomanip>
using std::cout;
using std::endl;

class Clock {
public:
    Clock(int h=0,int m=0,int s=0);
    Clock(const Clock& t);
    ~Clock() = default;
    
    void set_time(int h,int m=0,int s=0);
    void show_time() const;
    
private:
    int hour,minute,second;
};

Clock::Clock(int h,int m,int s):hour{h},minute{m},second{s}
{
    cout << "copy constructor called" << endl;
}


Clock::Clock(const Clock& t): hour{t.hour}, minute{t.minute},second{t.second} 
{
    cout << "copy constructor called" << endl;
}

void Clock::set_time(int h, int m, int s) 
{
    hour = h;
    minute = m;
    second = s;
}

void Clock::show_time() const
{
    using std::setw;
    using std::setfill;
    
    cout<< setfill('0') << setw(2) << hour << ":"<< setw(2) << minute << ":"<< setw(2) << second << endl;
}

Clock reset()
{
    return Clock(4,25,0);
}

int main()
{
    Clock c1(3,9,0);
    c1.show_time();
    
    c1=reset();
    c1.show_time();
    
    Clock c2(c1);
    c2.set_time(17);
    c2.show_time();    
}

实验任务4：

#include <iostream>

class X{
public:
    X();
    ~X();
    X(int m);
    X(const X& obj);
    X(X&& obj) noexcept;
    void show() const;
    
private:
    int data;
};

X::X(): data{42} 
{
    std::cout << "default constructor called.\n";
}

X::~X() 
{
    std::cout << "destructor called.\n";
}

X::X(int m): data{m} 
{
    std::cout << "constructor called.\n";
}

X::X(const X& obj): data{obj.data} 
{
    std::cout << "copy constructor called.\n";
}

X::X(X&& obj) noexcept: data{obj.data} 
{
    std::cout << "move constructor called.\n";
}

void X::show() const
{
    std::cout << data << std::endl;
}

int main()
{
    X x1;
    x1.show();
    
    X x2{2049};
    x2.show();
    
    X x3{x1};
    x3.show();
    
    X x4{ std::move(x2) };
    x4.show();    
}

分析：

X x1; 默认构造函数被调用 

X x2{2049};  参数构造函数被调用

X x3{x1};  复制构造函数被调用

X x4{ std::move(x2) }; 移动构造函数被调用

在程序结束前析构函数被调用