实验一 类与对象

实验任务2

使用C++语言特性中支持面向对象的语法，实现一个Point类来描述点的基础属性和操作。 

#include<iostream>
using namespace std;
class Point {
public:
    Point(int x0 = 1, int y0 = 2);
    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 << "constrctor called" << endl;
}
Point::Point(const Point& p) : x{ p.x }, y{ p.y }{
    cout << "copy constrctor called" << endl;
}
void Point::show()const {
    cout << "(" << x << "," << y << ")" << endl;
}
int main() {
    Point p1;
    p1.show();
    Point p2(4, 5);
    p2.show();
    Point p3 = p2;
    p3.show();
    Point p4{ p3 };
    p4.show();
    cout << p4.get_x() << endl;
}

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 实验任务3

使用C++语言特性中支持面向对象的语法，实现一个简单时钟类Clock。通过它实现对时钟 的设置、显示等基础操作。 

#include<bits/stdc++.h>
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;
    int minute;
    int 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(12, 0, 5);
    c1.show_time();
    c1 = reset();
    c1.show_time();
    Clock c2(c1);
    c2.show_time();

}

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 实验任务4

使用C++语言特性中支持面向对象的语法，实现一个抽象类X。它是对类和对象的基础操作 的一个抽象概括，覆盖了类的定义、实现、测试，包括各类构造函数、析构函数及其调用时机的观察。 

#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();
}

X x1; 默认构造函数调用；

X x2{ 2049 };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；
析构函数在对象的生存期即将结束的时候被调用；
即在 show() const; 之后调用； 

实验任务5
设计并实现一个矩形类Rectangle.

#include<bits/stdc++.h>
using namespace std;
class Rectangle {
private:
    double length, width;
public:
    Rectangle();
    Rectangle(double l, double w);
    Rectangle(const Rectangle& r);
    ~Rectangle() = default;
    double len()const{ return length; }
    double wide()const{ return width; }
    double area()const{ return length * width; }
    double circumference()const{ return 2 * (length + width); }
    void resize(double times);
    void resize(double l_times, double w_times);
};
Rectangle::Rectangle() :length{ 2.0 }, width{ 1.0 }{};
Rectangle::Rectangle(double l, double w) :length{ l }, width{ w }{};
Rectangle::Rectangle(const Rectangle& r) :length{ r.length }, width{ r.width }{};
void Rectangle::resize(double times) {
    length *= times;
    width *= times;
}
void Rectangle::resize(double l_times, double w_times) {
    length *= l_times;
    width *= w_times;
}
void output(const Rectangle& rect) {
    using namespace std;
    cout << fixed << setprecision(2);
    cout << "矩阵信息：" << endl;
    cout << left<< setw(8) << "长："
                << rect.len()<<endl;
    cout <<left << setw(8) << "宽："
                << rect.wide() << endl;
    cout << left<< setw(8) << "面积："
                << rect.area() << endl;
    cout << left<< setw(8) << "周长："
                <<rect.circumference() << endl;
    cout << 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);
}