实验1

Test 1

#include<iostream>
#include<cstring>
#include<vector>


using namespace std;

int main()
{
	string s1;
	string s2{"c plus plus"};
	string s3{s2};
	string s4 = s2;
	
	s1 = "oop";
	
	vector<string> v1;
	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 << "ouput2: ";
	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;
}

Test 2

#include <iostream>
#include <vector>

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, 7); 
    p1.show();
    
    Point p2 = p1; 
    p2.show();

    Point p3{p2}; 
    p3.show();
    cout << p3.get_x() << endl;
}

Test 3

#include <iostream>
#include <iomanip>
using std::cout;
using std::endl;
// 定义时钟类Clock
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;
};
// 类Clock实现
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 << ":";
	cout << setw(2) << minute << ":";
    cout << setw(2) << second << endl;
}
// 普通函数定义
Clock reset() {
return Clock(0, 0, 0); // 构造函数被调用
}
int main()
{
Clock c1(12, 0, 5); // 构造函数被调用
c1.show_time();
c1 = reset(); // 理论上：复制构造函数被调用
c1.show_time();
Clock c2(c1); // 复制构造函数被调用
c2.set_time(6);
c2.show_time();
}

Test 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 << "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();
	return 0;
}

解释

47.48行，默认构造函数X()被调用；
50.51行，构造函数X(int m)被调用；
53.54行，复制构造函数X(const X& obj)被调用；
56.57行，移动构造函数X(X&& obj) noexcept被调用。
在对象生命周期结束时，析构函数被调用，跟构造函数的调用顺序相反。

Test 5

// stack

#include <iostream>
#include <iomanip>
// 矩形类Rectangle的定义和实现
// 补足代码
// ×××
// 普通函数, 用于输出矩形信息

using namespace std;

class Rectangle
{
  public:
	Rectangle(float l = 2.0,float w = 1.0) : length{l},width{w} {}
	Rectangle(const Rectangle &obj):
	length{obj.length},width{obj.width}{}
			~Rectangle()=default;
	
	
	//void output();
	float len() const {return length;}
	float wide() const {return width;}
	float area() const {return length*width;}
	float circumference() const {return 2*(length+width);}
	
	
	void resize(int times);
    void resize(int l_times,int w_times);
	
	private :
	float 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:\n";
	cout<<std::left<<setw(7)<<"长:"<<std::right<<
		fixed<<setprecision(2)<<setw(5)<<rect.len()<<endl;
	cout<<std::left<<setw(7)<<"宽:"<<std::right<<
		fixed<<setprecision(2)<<setw(5)<<rect.wide()<<endl;
	cout<<std::left<<setw(7)<<"面积:"<<std::right<<
		fixed<<setprecision(2)<<setw(5)<<rect.area()<<endl;
	cout<<std::left<<setw(7)<<"周长:"<<std::right<<
		fixed<<setprecision(2)<<setw(5)<<rect.circumference()<<endl;
	cout<<endl;
}

//主函数，测试Rectangle类
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);
}