类和对象_基础编程1

实验任务1

task1.cpp：

// 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();
}

运行测试截图：

 

实验任务2

task2.cpp：

#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();
}

运行测试截图：

 

 

实验任务3

task3.cpp：

// 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();
T::disply_count();
}
// 主函数
int main() {
cout << "============测试类T============" << endl;
test();
cout << endl;
cout << "============测试友元函数func()============" << endl;
func();
}

运行测试截图：

 

 

实验任务4

task4.cpp：

#include <iostream>
#include <string>
#include <iomanip>
using namespace std;
// 矩形类Rect的定义
class Rect {
    static int count; // 静态成员变量，记录矩形对象的数量
public:
double length;
    double width;
    static string doc; // 静态成员变量，矩形类的信息
    Rect() : length(2.00), width(1.00) 
    {
        count++;
    }
    Rect(double l, double w) : length(l), width(w) 
    {
        count++;
    }
    Rect(const Rect& r) : length(r.length), width(r.width) 
    {
        count++;
    }
    ~Rect()
    {
        count--;
    }
    void resize(double l, double w) 
    {
        length = l;
        width = w;
    }
    void resize(double s) 
    {
        length = s;
        width = s;
    }
    double area() const
    {
        return length * width;
    }
    double perimeter() const
    {
        return 2 * (length + width);
    }

    static int size_info() 
    {
        return count;
    }
};
int Rect::count = 0;
string Rect::doc = "a simple Rect class";
// 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);
    cout << "长:    " << r.length << endl;
    cout << "宽:    " << r.width << endl;
    cout << "面积:  " << r.area() << endl;
    cout << "周长:  " << r.perimeter() << 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;
    return 0;
}

运行测试截图：

 

实验任务5

task5.cpp:

#include <iostream>
#include <cmath>
using namespace std;
// 复数类Complex的定义
class Complex {
private:
    double real; // 实部
    double imag; // 虚部
public:
    Complex() : real(0), imag(0) {}
    Complex(double r) : real(r), imag(0) {}
    Complex(double r, double i) : real(r), imag(i) {}
    Complex(const Complex& c) : real(c.real), imag(c.imag) {}
    double get_imag() const {
        return imag;
    }
    void show() const {
        cout << real;
        if (imag >= 0) {
            cout << " + " << imag << "i";
        } else {
            cout << " - " << -imag << "i";
        }
    }
    friend double abs(const Complex& c);
    friend bool is_equal(const Complex& c1, const Complex& c2);
    friend Complex add(const Complex& c1, const Complex& c2);
    void add(const Complex& c) {
        real += c.real;
        imag += c.imag;
    }
    Complex& operator+=(const Complex& c) {
        add(c);
        return *this;
    }
};
// 求复数的绝对值
double abs(const Complex& c) {
    return sqrt(c.real * c.real + c.imag * c.imag);
}
// 判断两个复数是否相等
bool is_equal(const Complex& c1, const Complex& c2) {
    return c1.real == c2.real && c1.imag == c2.imag;
}
// 复数相加
Complex add(const Complex& c1, const Complex& c2) {
    Complex result;
    result.real = c1.real + c2.real;
    result.imag = c1.imag + c2.imag;
    return result;
}

// 复数类Complex的测试
void test() {
    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 += c2;
    cout << "c1 += c2, " << "c1 = ";
    c1.show();
    cout << endl;
}

int main() {
    test();
    return 0;
}

运行测试截图：