实验1 类和对象（1）

1.实验任务1

task1_1

程序源码

#include<iostream>
#include<string>
#include<vector>
int main()
{
    using namespace std;
    
    string s1;
    string s2{"c plus plus"};
    string s3{s2};
    string s4=s2;
    
    s1="oop";
    
    vector<string> v1;
    v1.push_back(s1);
    v1.push_back(s2+"1");
    v1.push_back(s3+"2");
    v1.push_back(s4+"3");
    
    cout<<"output1:"<<endl;
    for(auto item:v1)
        cout<<item<<endl;
        
    cout<<"output2:";
    for(auto p=v1.begin();p!=v1.end();++p)
        cout<<*p<<endl;
    
    cout<<"output3:"<<endl;
    for(auto i=0;i<v1.size();++i)
        cout<<v1[i]<<endl;
    
    vector<string> v2{v1.rbegin(),v1.rend()};
    cout<<"v2:"<<endl;
    for(auto item :v2)
        cout<<item<<endl;
}

测试结果

task1_2

程序源码

#include<iostream>
#include<string>
#include<vector>
#include<cmath>
#include<cstdlib>
#include<time.h>

template <typename T>
void output(const T& obj)
{
    for(auto item: obj)
        std::cout<<item<<" ";
    std::cout<<std::endl;
}

int main()
{
    using namespace std;
    
    vector<int> v1{1,9,8,4};
    v1.insert(v1.begin(),2022);
    v1.insert(v1.end(),2023);
    
    cout<<"v1: ";
    output(v1);
    
    v1.pop_back();
    v1.erase(v1.begin());
    cout<<"v1: ";
    output(v1);
    
    vector<string> v2{"《1984》","《动物农场》","《美丽新世界》"};
    cout<<"v2: ";
    output(v2);
}

测试结果

 

2.实验任务2

 程序源码（已更换测试数据）

#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(5,6);
    p1.show();
    
    Point p2=p1;
    p2.show();
    
    Point p3{p2};
    p3.show();
    cout<<p3.get_x()<<endl;    
}

测试结果（已更换测试数据）

 

3.实验任务3

程序源码（已更换测试数据）

#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(10,0,5);
c1.show_time() ;

c1=reset();
c1.show_time();

Clock c2{c1};
c2.set_time(2);
c2.show_time();
}

 测试结果（已更换测试数据）

4.实验任务4

程序源码（已更换测试数据）

#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{40}{
    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{2048};
    x2.show();
    
    X x3{x2};
    x3.show();
    
    X x4{std::move(x1)};
    x4.show();
}

 测试结果（已更换测试数据）

 分析

X x1;//默认构造函数被调用

X x2{2048};//定义的构造函数被调用

X x3{x2};//复制构造函数被调用

X x4{std::move(x1)};//移动构造函数被调用
析构函数在x4.show()后调用，顺序是x4,x3,x2,x1

5.实验任务5

程序源码

#include <iostream>
#include <iomanip>

class Rectangle
{
public:
    Rectangle();
    Rectangle(double l, double w);
    Rectangle(const Rectangle & obj);
    ~Rectangle() = default;
    
    double len() const;
    double wide() const;
    double area() const;
    double circumference() const;
    void resize(int times);
    void resize(int l_times, int w_times);

private:
    double length, width;
};

Rectangle::Rectangle() : length{2.00}, width{1.00} {}
Rectangle::Rectangle(double l, double w) : length{l}, width{w} {}
Rectangle::Rectangle(const Rectangle & obj) : length{obj.length}, width{obj.width} {}

double Rectangle::len() const { return length; }
double Rectangle::wide() const { return width; }
double Rectangle::area() const { return length * width; };
double Rectangle::circumference() const { return 2 * (length + 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 << "矩阵信息:" << endl;
    cout << fixed << setprecision(2);
    cout <<setfill(' ')<< setw(8) <<left<< "长:" << rect.len() << endl
         <<setfill(' ')<< setw(8) <<left<< "宽:" << rect.wide() << endl
         <<setfill(' ')<< setw(8) <<left<< "面积:" << rect.area() << endl
         <<setfill(' ')<< setw(8) <<left<< "周长:" << 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);
}

测试结果