实验1 类和对象

// 标准库string, vector, array基础用法
#include <iostream>
#include <string>
#include <vector>
#include <array>
// 函数模板
// 对满足特定条件的序列类型T对象，使用范围for输出
template<typename T>
void output1(const T &obj) {
for(auto i: obj)
std::cout << i << ", ";
std::cout << "\b\b \n";
}
// 函数模板
// 对满足特定条件的序列类型T对象，使用迭代器输出
template<typename T>
void output2(const T &obj) {
for(auto p = obj.begin(); p != obj.end(); ++p)
std::cout << *p << ", ";
std::cout << "\b\b \n";
}
// array模板类基础用法
void test_array() {
using namespace std;
array<int, 5> x1; // 创建一个array对象，包含5个int元素，未初始化
cout << "x1.size() = " << x1.size() << endl; // 输出元素个数
x1.fill(42); // 把x1的所有元素都用42填充
x1.at(0) = 999; // 把下标为0的元素值修改为999
x1[4] = -999; // 把下表为4的元素值修改为-999
cout << "x1: ";
output1(x1); // 调用模板函数output1输出x1
cout << "x1: ";
output2(x1); // 调用模板函数output1输出x1
array<int, 5> x2{x1};
cout << boolalpha << (x1 == x2) << endl;
x2.fill(22);
cout << "x2: ";
output1(x2);
swap(x1, x2); // 交换array对象x1, x2
cout << "x1: ";
output1(x1);
cout << "x2: ";
output1(x2);
}
// vector模板类基础用法
void test_vector() {
using namespace std;
vector<int> v1;
cout << v1.size() << endl; // 输出目前元素个数
cout << v1.max_size() << endl; // 输出元素个数之最大可能个数
v1.push_back(55); // 在v1末尾插入元素
cout << "v1: ";
output1(v1);
vector<int> v2 {1, 0, 5, 2};
v2.pop_back(); // 从v2末尾弹出一个元素
v2.erase(v2.begin()); // 删除v2.begin()位置的数据项
v2.insert(v2.begin(), 999); // 在v1.begin()之前的位置插入
v2.insert(v2.end(), -999); // 在v1.end()之前的位置插入
cout << v2.size() << endl;
cout << "v2: ";
output2(v2);
vector<int> v3(5, 42); //创建vector对象，包含5个元素，每个元素值都是42
cout << "v3: ";
output1(v3);
vector<int> v4(v3.begin(), v3.end()-2); // 创建vector对象，以v3对象的[v3.begin(), v3.end()-2)区间作为元素值
cout << "v4: ";
output1(v4);
}
// string类基础用法
void test_string() {
using namespace std;
string s1{"oop"};
cout << s1.size() << endl;
for(auto &i: s1)
i -= 32;
s1 += "2023";
s1.append(", hello");
cout << s1 << endl;
}
int main() {
using namespace std;
cout << "===========测试1: array模板类基础用法===========" << endl;
test_array();
cout << "\n===========测试2: vector模板类基础用法===========" << endl;
test_vector();
cout << "\n===========测试3: string类基础用法===========" << endl;
test_string();
}

#include <iostream>
#include <complex>
// 测试标准库提供的复数类模板complex
void test_std_complex() {
    using namespace std;
    complex<double> c1{ 3, 4 }, c2{ 4.5 };
    const complex<double> c3{ c2 };
    cout << "c1 = " << c1 << endl;
    cout << "c2 = " << c2 << endl;
    cout << "c3 = " << c3 << endl;
    cout << "c3.real = " << c3.real() << ", " << "c3.imag = " << c3.imag()
        << endl;
    cout << "c1 + c2 = " << c1 + c2 << endl;
    cout << "c1 - c2 = " << c1 - c2 << endl;
    cout << "abs(c1) = " << abs(c1) << endl; // abs()是标准库数学函数，对复数取模
        cout << boolalpha; // 设置bool型值以true/false方式输出
    cout << "c1 == c2: " << (c1 == c2) << endl;
    cout << "c3 == c2: " << (c3 == c2) << endl;
    complex<double> c4 = 2;
    cout << "c4 = " << c4 << endl;
    c4 += c1;
    cout << "c4 = " << c4 << endl;
}
int main() {
    test_std_complex();
}

// 一个简单的类T：定义、使用
#include <iostream>
#include <string>
using namespace std;
// 类T的声明
class T {
public:
    T(int x = 0, int y = 0); // 带有默认形值的构造函数
    T(const T& t); // 复制构造函数
    T(T&& t); // 移动构造函数
    ~T(); // 析构函数
    void set_m1(int x); // 设置T类对象的数据成员m1
    int get_m1() const; // 获取T类对象的数据成员m1
    int get_m2() const; // 获取T类对象的数据成员m2
    void display() const; // 显示T类对象的信息
    friend void func(); // 声明func()为T类友元函数
private:
    int m1, m2;
public:
    static void disply_count(); // 类方法，显示当前T类对象数目
public:
    static const string doc; // 类属性，用于描述T类
    static const int max_count; // 类属性，用于描述T类对象的上限
private:
    static int count; // 类属性，用于描述当前T类对象数目
};
// 类的static数据成员：类外初始化
const string T::doc{ "a simple class" };
const int T::max_count = 99;
int T::count = 0;
// 类T的实现
T::T(int x, int y) : m1{ x }, m2{ y } {
    ++count;
    cout << "constructor called.\n";
}
T::T(const T& t) : m1{ t.m1 }, m2{ t.m2 } {
    ++count;
    cout << "copy constructor called.\n";
}
T::T(T && t) : m1{ t.m1 }, m2{ t.m2 } {
    ++count;
    cout << "move constructor called.\n";
}
T::~T() {
    --count;
    cout << "destructor called.\n";
}
void T::set_m1(int x) {
    m1 = x;
}
int T::get_m1() const {
    return m1;
}
int T::get_m2() const {
    return m2;
}
void T::display() const {
    cout << m1 << ", " << m2 << endl;
}
// 类方法
void T::disply_count() {
    cout << "T objects: " << count << endl;
}
// 友元函数func()：实现
void func() {
    T t1;
    t1.set_m1(55);
    t1.m2 = 77; // 虽然m2是私有成员，依然可以直接访问
    t1.display();
}
// 测试
void test() {
    cout << "T class info: " << T::doc << endl;
    cout << "T objects max_count: " << T::max_count << endl;
    T::disply_count();
    T t1;
    t1.display();
    t1.set_m1(42);
    T t2{ t1 };
    t2.display();
    T t3{ std::move(t1) };
    t3.display();
    t1.display();
}
// 主函数
int main(){
    cout << "============测试类T============" << endl;
    test();
    cout << endl;
    cout << "============测试友元函数func()============" << endl;
    func();
}

#include <iostream>
#include <string>
#include <iomanip>
using namespace std;
// 矩形类Rect的定义
class Rect {
private:
    double length, width;
    static int size;
public:
    //对象方法
    Rect(double l = 2.0, double w = 1.0);
    Rect(const Rect &r);//复制构造函数
    ~Rect();
    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);
public:
    static const string doc;
    static int size_info() {
        return size;
    }

};
int Rect::size = 0;
const string Rect::doc{ "a simple Rect class" };
//对象方法
Rect::Rect(double l, double w) {
    length = l;
    width = w;
    size++;
}
void Rect::resize(double times) {
    length *= times;
    width *= times;
}
void Rect::resize(double l_times, double w_times) {
    length *= l_times;
    width *= w_times;
}
Rect::~Rect() {
    size--;
}
Rect::Rect(const Rect& r){
    length = r.length;
    width = r.width;
    size++;
}
// 普通函数：输出矩形信息
void output(const Rect &r) {
        cout << "矩形信息: " << endl;
    cout << fixed << setprecision(2); // 控制输出格式：以浮点数形式输出，小数部分保留两位
    cout << "长度" << r.len() << endl;
    cout << "宽度" << r.wide() << endl;
    cout << "周长" << r.circumference() << endl;
    cout << "面积" << r.area() << endl;
}
// 测试代码
void test() {
    cout << "矩形类信息: " << Rect::doc << endl;
    cout << "当前矩形对象数目: " << Rect::size_info() << endl;
    Rect r1;
    output(r1);
    Rect r2(4, 3);
    output(r2);
    Rect r3(r2);
    r3.resize(2);
    output(r3);
    r3.resize(5, 2);
    output(r3);
    cout << "当前矩形对象数目: " << Rect::size_info() << endl;
}
// 主函数
int main() {
    test();
    cout << "当前矩形对象数目: " << Rect::size_info() << endl;
}

#include <iostream>
#include <cmath>
class Complex
{
private:
    double real, imag;
public:
    Complex(double a = 0, double b = 0) :real(a), imag(b) {}
    Complex(const Complex &x);
    ~Complex() {};
    double get_real() { return real; }
    double get_imag() const { return imag; }
    void show() const;
    void add(const Complex &z);
    friend Complex add(const Complex &k,const Complex &l);
    friend bool is_equal(const Complex &aaa,const Complex &bbb);
    friend double abs(const Complex &x);
};
Complex::Complex(const Complex& x)
{
    real = x.real;
    imag = x.imag;
}
void Complex::show() const
{
    if (imag > 0) {
        std::cout << real << "+" << imag << "i";
    }
    else if (imag < 0)
        std::cout << real << imag << "i";
    else
        std::cout << real;
}
 void Complex::add(const Complex &z)
{
     real = real + z.real;
     imag = imag + z.imag;
 }
 Complex add(const Complex &k,const Complex &l)
 {
     Complex s;
     s.real=k.real+l.real;s.imag=k.imag+l.imag;
     return (s);
 }
 bool is_equal(const Complex &aaa,const Complex &bbb)
 {
     if (aaa.real == bbb.real && aaa.imag == bbb.imag)
         return (true);
     else
         return (false);
}
double abs(const Complex &x)
{
    return(sqrt(x.real * x.real + x.imag * x.imag));
}

void test() {
    using namespace std;
    Complex c1(3, -4);
    const Complex c2(4.5);
    Complex c3(c1);
    cout << "c1 = ";
    c1.show();
    cout << endl;
    cout << "c2 = ";
    c2.show();
    cout << endl;
    cout << "c2.imag = " << c2.get_imag() << endl;
    cout << "c3 = ";
    c3.show();
    cout << endl;
    cout << "abs(c1) = ";
    cout << abs(c1) << endl;
    cout << boolalpha;
    cout << "c1 == c3 : " << is_equal(c1, c3) << endl;
    cout << "c1 == c2 : " << is_equal(c1, c2) << endl;
    Complex c4;
    c4 = add(c1, c2);
    cout << "c4 = c1 + c2 = ";
    c4.show();
    cout << endl;
    c1.add(c2);
    cout << "c1 += c2, " << "c1 = ";
    c1.show();
    cout << endl;
}
int main() {
    test();
}