实验1 类和对象（1）

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 << "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(4, 5);
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 << "copy constructor called" << endl;
}
Clock::Clock(const Clock& t) :hour{ t.hour }, minute{ t.minute },
second{ t.second } {
    cout << "copy consttructor 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(17, 29, 45);
    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 date;

};
X::X() :date{ 42 } {
    std::cout << "default constructor called.\n";
}
X::X(int m) :date{ m } {
    //date = m;
    std::cout << "constructor called.\n";
}
X::~X() {
    std::cout << "destructor called.\n";
}
X::X(const  X& obj) :date{ obj.date } {
    std::cout << "copy destructor called.\n";
}
X::X(X&& obj)noexcept :date{ obj.date } {
    std::cout << "move destructor called.\n";
}
void X::show()const {
    std::cout << date << 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();
}

 

在执行 X x1;时，不带参数的默认构造函数被调用；

在执行 X x2{2049};时，带参数的构造函数被调用；

在执行 X x3{x1};时，复制构造函数被调用；

在执行 X x4{std::move(x2)};时，移动构造函数被调用，将x2 的值给了x4;

通过运行结果可知，析构函数是在所有程序执行完毕后，才被调用的，将x1 x2 x3 x4所占的资源与对象进行了销毁。

 

实验任务五   源代码及运行结果

1 #include<iostream>
 2 #include<iomanip>
 3 class Rectangle{
 4 public:
 5       Rectangle();
 6       Rectangle(double l, double w);
 7       Rectangle(Rectangle& obj);
 8 
 9       double len()const { return length; }
10       double wide()const { return width; }
11       double area() const { return length * width; }
12       double circumference () const { return 2 * (length + width); }
13       void resize(int times);
14       void resize(int l_times, int w_times);
15 ; private:
16     double length, width;
17 };
18 Rectangle::Rectangle( ) {
19     length = 2.0;
20     width = 1.0;
21 }
22 Rectangle::Rectangle(double l, double w) {
23     length = l;
24     width = w;
25 }
26 
27 Rectangle::Rectangle ( Rectangle& rect){
28     length = rect.length;
29     width = rect.width;
30 }
31 void Rectangle::resize(int times) {
32     length = length * times;
33     width = width * times;
34 }
35 void Rectangle::resize(int l_times, int w_times) {
36     length = length * l_times;
37     width = width * w_times;
38 }
39 //普通函数，用于输出矩阵信息
40 void output(const Rectangle& rect)
41 {
42     using namespace std;
43     cout << "矩形信息：" << endl;
44     cout << "长：    " << fixed << setprecision(2) << rect.len() << endl;
45     cout << "宽：    " << fixed << setprecision(2) << rect.wide() << endl;
46     cout << "面积：  " << fixed << setprecision(2) << rect.area() << endl;
47     cout << "周长：  " << fixed << setprecision(2) << rect.circumference() << endl;
48     cout << endl;
49 }
50 int main() {
51     Rectangle rect1; 
52     output(rect1);
53     Rectangle rect2(10, 5); // 带有两
 

55     Rectangle rect3(rect1); // 复制构造函数被调用
56     rect3.resize(2); // 矩形rect3的长和宽同时缩放2倍
57     output(rect3);
58     rect3.resize(5, 2); // 矩形rect3的长缩放5倍, 宽缩放2倍
59     output(rect3);
60 }