实验1 类与对象

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(3,4);
    p1.show();
    Point p2=p1;
    p2.show();
    Point p3{p2};
    p3.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<<"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(0,0,0);
 }
 int main()
 {
     Clock c1(12,0,5);
     c1.show_time();
     c1 = reset();
    c1.show_time();
     Clock c2(c1); 
    c2.set_time(6);
    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<<"constructor 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();
}

 构造函数被调用：X x1; 调用了默认的构造函数。  X x2{2049};构造函数被编译器自动调用 。   X x3{x1};  复制构造函数被编译器自动调用。  X x4{std::move(x2)};移动构造函数被编译器调用。

 析构函数是在程序结束之前才进行运行，最后对x1,x2,x3,x4进行销毁。

实验任务5

#include <iostream>
#include <iomanip>
class Rectangle{
    public:
        Rectangle(double length=2.0,double width=1.0);
        Rectangle(const Rectangle& rect);
        ~Rectangle()=default;
        double len() const {return length;}
        double wide() const {return width;}
        double area() const {return length*width;}
        double circumference() const {return(width+length)*2;}
        void resize(int times);
        void resize(int l_times,int w_times);
    private:
        double length,width;
};
Rectangle::Rectangle(double l0,double w0):length{l0},width{w0}{}
Rectangle::Rectangle(const Rectangle& r): length{r.length},width{r.width}{}
void Rectangle::resize(int times){
    length*=times;
    width*=times;
}
void Rectangle::resize(int l_times,int w_times)
{
   length*=l_times;
   width*=w_times;
}
void output(const Rectangle &rect) {
using namespace std;
    cout << "矩形信息: \n";
    cout<<"长：  "<<fixed<<setprecision(2)<<rect.len()<<endl;
    cout<<"宽：  "<<fixed<<setprecision(2)<<rect.wide()<<endl;
    cout<<"面积："<<fixed<<setprecision(2)<<rect.area()<<endl;
    cout<<"周长："<<fixed<<setprecision(2)<<rect.circumference()<<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);
}