实验一 类与对象(1)

实验二:

代码如下:

 

#include<iostream>
using namespace std;

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 << "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(1217,1118);
    p1.show();
    
    Point p2 = p1;
    p2.show();
    
    Point p3{p2};
    p3.show();
    cout << p3.get_x() << endl;
}

 

运行结果:

 

 

 

 

实验三:

代码如下:

 

#include<iostream>
#include<iomanip>
using namespace std;

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 << "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 {
    cout << setfill('0') << setw(2) << hour << ":" << setw(2) << minute << ":"
    << setw(2) << second << endl;
}
Clock reset() {
    return Clock(0, 0, 0);
}

int main()
{
    Clock c1(2,12,17);
    c1.show_time();
    
    c1 = reset();
    c1.show_time();
    
    Clock c2(c1);
    c2.set_time(2,11,18);
    c2.show_time();
}

 

运行结果:

 

 

 

 

实验四:

代码如下:

 

#include<iostream>
using namespace std;
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();
}

 

运行结果:

分析:

第34行:  X x1;            默认构造函数被调用。

第37行:  X x2{2049};         构造函数被调用。

第40行:  X x3{x1};          复制构造函数被调用。

第43行:  X x4{ std::move(x2) };    移动构造函数被调用。

第44行,函数运行结束,对象即将消失时,析构函数被调用,析构函数按对象被定义的顺序,从后往前清除。

 

 

实验五:

代码如下:

 

#include<iostream>
#include <iomanip>
using namespace std;

class Rectangle{
    public:
        Rectangle();
        Rectangle(double l,double w);
        Rectangle(const Rectangle &rect);
        ~Rectangle()=default;
        double get_len() {return length;}
        double get_wide() {return width;}
        double area() {return length*width;}
        double circumference() {return 2*(length+width);}
        double resize(double times) {length=times*length,width=times*width;}
        double resize(double l_times,double w_times) { length*=l_times,width*=w_times;}
    private:
        double length,width;
}; 
Rectangle::Rectangle(): length{2.0},width{1.0}{}

Rectangle::Rectangle(double l,double w): length{l},width{w}{}

Rectangle::Rectangle(const Rectangle& rect): length{rect.length},width{rect.width}{}

void output(const Rectangle &rect) {
    Rectangle a=rect;
    cout << "矩形信息: \n";
    cout << fixed << setprecision(2);
    cout << "长:     " << a.get_len() <<endl
    << "宽:     " << a.get_wide() <<endl
    <<"面积:   " << a.area() <<endl
    <<"周长:   " << a.circumference() << endl <<endl;

}
int main()
{
    Rectangle rect1;
    output(rect1);
    
    Rectangle rect2(10, 5);
    output(rect2);
    
    Rectangle rect3(rect1);
    rect3.resize(2);
    output(rect3);
    
    rect3.resize(5, 2);
    output(rect3);
}

 

运行结果:

 

 

 

 

posted @ 2022-10-03 17:35  lovessr  阅读(5)  评论(0编辑  收藏  举报