实验2 类和对象_基础编程

wxdyyds / 2025-02-10 / 原文

1.实验任务一：

t.h:

#pragma once

#include <string>

// 类T: 声明
class T {
// 对象属性、方法
public:
    T(int x = 0, int y = 0);   // 普通构造函数
    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 adjust(int ratio);      // 按系数成倍调整数据
    void display() const;           // 以(m1, m2)形式显示T类对象信息

private:
    int m1, m2;

// 类属性、方法
public:
    static int get_cnt();          // 显示当前T类对象总数

public:
    static const std::string doc;       // 类T的描述信息
    static const int max_cnt;           // 类T对象上限

private:
    static int cnt;         // 当前T类对象数目

// 类T友元函数声明
    friend void func();
};
//const std::string T::doc{ "a simple class sample" };
//const int T::max_cnt = 999;
//int T::cnt = 0;
// 普通函数声明
void func();

t.cpp:

// 类T: 实现
// 普通函数实现

#include "t.h"
#include <iostream>
#include <string>

using std::cout;
using std::endl;
using std::string;

// static成员数据类外初始化
const std::string T::doc{ "a simple class sample" };
const int T::max_cnt = 999;
int T::cnt = 0;


// 对象方法
T::T(int x, int y): m1{x}, m2{y} { 
    ++cnt; 
    cout << "T constructor called.\n";
} 

T::T(const T &t): m1{t.m1}, m2{t.m2} {
    ++cnt;
    cout << "T copy constructor called.\n";
}

T::T(T &&t): m1{t.m1}, m2{t.m2} {
    ++cnt;
    cout << "T move constructor called.\n";
}    

T::~T() {
    --cnt;
    cout << "T destructor called.\n";
}           

void T::adjust(int ratio) {
    m1 *= ratio;
    m2 *= ratio;
}    

void T::display() const {
    cout << "(" << m1 << ", " << m2 << ")" ;
}     

// 类方法
int T::get_cnt() {
   return cnt;
}

// 友元
void func() {
    T t5(42);
    t5.m2 = 2049;
    cout << "t5 = "; t5.display(); cout << endl;
}

task1.cpp:

#include "t.h"
#include <iostream>

using std::cout;
using std::endl;

void test();

int main() {
    test();
    cout << "\nmain: \n";
    cout << "T objects'current count: " << T::get_cnt() << endl;
}

void test() {
    cout << "test class T: \n";
    cout << "T info: " << T::doc << endl;
    cout << "T objects'max count: " << T::max_cnt << endl;
    cout << "T objects'current count: " << T::get_cnt() << endl << endl;


    T t1;
    cout << "t1 = "; t1.display(); cout << endl;

    T t2(3, 4);
    cout << "t2 = "; t2.display(); cout << endl;

    T t3(t2);
    t3.adjust(2);
    cout << "t3 = "; t3.display(); cout << endl;

    T t4(std::move(t2));
    cout << "t3 = "; t4.display(); cout << endl;

    cout << "T objects'current count: " << T::get_cnt() << endl;

    func();
}

运行截图：

问题一：

原因：头文件中未声明func()函数，导致task1引用头文件时未能找到func()函数。

问题二：

1.普通构造函数
功能：
用于初始化新创建的对象。
可以有零个或多个参数，用于给对象的成员变量赋初值。
调用时机：
当使用 new 关键字创建对象时。
当对象被声明并初始化时，例如 Example obj; 或 Example obj(参数); 。
2.复制构造函数
功能：
用于创建一个新对象，该对象是另一个已存在对象的副本。
它通过复制传入对象的资源来初始化新对象。
调用时机：
当一个对象以值传递的方式被传递给函数时。
当一个对象被分配给另一个对象时。
当一个对象被返回时（如果函数返回局部对象）。
当使用标准库容器时，容器可能会在内部复制对象。
当使用 std::copy 等算法时。
当使用 std::vector 等容器的 emplace_back 方法时。
3.移动构造函数
功能：
用于创建一个新对象，该对象接管另一个对象的资源。
它通过“移动”传入对象的资源来初始化新对象，而不是复制这些资源。
调用时机：
当一个对象以右值引用的方式被传递给函数时。
当一个对象被分配给另一个对象，且源对象是一个临时对象或右值时。
当一个对象被返回时，且返回的是一个局部对象或右值时。
当使用标准库容器时，容器可能会在内部移动对象。
当使用 std::move 将一个对象转换为右值时。
4.析构函数
功能：
用于在对象生命周期结束时进行清理工作。
负责释放对象所占用的资源，如动态分配的内存、文件句柄、网络连接等。
调用时机：
当一个对象离开其作用域时（例如局部对象）。
当一个动态分配的对象（使用 new 创建的对象）被删除时（使用 delete ）。
当一个对象被销毁，例如当一个包含对象的容器被销毁时。
5.总结
普通构造函数负责对象的初始化。
复制构造函数负责创建一个对象的副本。
移动构造函数负责创建一个对象，并从另一个对象中转移资源。
析构函数负责在对象生命周期结束时进行资源清理。
问题三：

2.实验任务二：

Complex.h:

#include <iostream>
#pragma once
class Complex
{
public:
    Complex(double x=0, double y=0);
    Complex(const Complex& p);
    ~Complex();
    void add(const Complex& p);
    double get_real() const;
    double get_imag() const;
    friend Complex add(const Complex& p1, const Complex& p2);
    friend bool is_equal(const Complex& p1, const Complex& p2);
    friend bool is_not_equal(const Complex& p1, const Complex& p2);
    friend void output(const Complex& p);
    friend double abs(const Complex& p);
    static const std::string doc;
private:
    double real, imag;
};

Complex.cpp:

#include "Complex.h"
#include <cmath>
double Complex::get_real() const
{
    return real;
}
double Complex::get_imag() const
{
    return imag;
}
void Complex::add(const Complex& p)
{
    real = real + p.real;
    imag = imag + p.imag;
}
Complex::Complex(double x, double y):real{x},imag{y}{}
Complex::Complex(const Complex& p):real{ p.real },imag{ p.imag }{}
Complex::~Complex(){}
Complex add(const Complex& p1, const Complex& p2)
{
    return Complex(p1.real + p2.real, p1.imag + p2.imag);
}
bool is_equal(const Complex& p1, const Complex& p2)
{
    if (p1.real == p2.real && p1.imag == p2.imag)
    {
        return 1;
    }
    else
    {
        return 0;
    }
}
bool is_not_equal(const Complex& p1, const Complex& p2)
{
    if (p1.real == p2.real && p1.imag == p2.imag)
    {
        return 0;
    }
    else
    {
        return 1;
    }
}
void output(const Complex& p)
{
    if (p.imag >= 0)
    {
        std::cout << p.real << " + " << p.imag << "i";
    }
    else
    {
        std::cout << p.real <<  " - " <<(-1.0)*p.imag << "i";
    }
}
double abs(const Complex& p)
{
    return sqrt(p.real * p.real + p.imag * p.imag);
}
const std::string Complex::doc{ "a simplfified Complex class" };

task2.cpp:

// 待补足（多文件组织代码时，需要包含的头文件）
#include <iostream>
#include "Complex.h"
using std::cout;
using std::endl;
using std::boolalpha;

void test() {
    cout << "类成员测试: " << endl;
    cout << Complex::doc << endl;

    cout << endl;

    cout << "Complex对象测试: " << endl;
    Complex c1;
    Complex c2(3, -4);
    const Complex c3(3.5);
    Complex c4(c3);

    cout << "c1 = "; output(c1); cout << endl;
    cout << "c2 = "; output(c2); cout << endl;
    cout << "c3 = "; output(c3); cout << endl;
    cout << "c4 = "; output(c4); cout << endl;
    cout << "c4.real = " << c4.get_real() << ", c4.imag = " << c4.get_imag() << endl;

    cout << endl;

    cout << "复数运算测试: " << endl;
    cout << "abs(c2) = " << abs(c2) << endl;
    c1.add(c2);
    cout << "c1 += c2, c1 = "; output(c1); cout << endl;
    cout << boolalpha;
    cout << "c1 == c2 : " << is_equal(c1, c2) << endl;
    cout << "c1 != c3 : " << is_not_equal(c1, c3) << endl;
    c4 = add(c2, c3);
    cout << "c4 = c2 + c3, c4 = "; output(c4); cout << endl;
}

int main() {
    test();
}

运行截图：

3.实验任务三：

#include <iostream>
#include <complex>

using std::cout;
using std::endl;
using std::boolalpha;
using std::complex;

void test() {
    cout << "标准库模板类comple测试: " << endl;
    complex<double> c1;
    complex<double> c2(3, -4);
    const complex<double> c3(3.5);
    complex<double> c4(c3);

    cout << "c1 = " << c1 << endl;
    cout << "c2 = " << c2 << endl;
    cout << "c3 = " << c3 << endl;
    cout << "c4 = " << c4 << endl;
    cout << "c4.real = " << c4.real() << ", c4.imag = " << c4.imag() << endl;
    cout << endl;

    cout << "复数运算测试: " << endl;
    cout << "abs(c2) = " << abs(c2) << endl;
    c1 += c2;
    cout << "c1 += c2, c1 = " << c1 << endl;
    cout << boolalpha;
    cout << "c1 == c2 : " << (c1 == c2) << endl;
    cout << "c1 != c3 : " << (c1 != c3) << endl;
    c4 = c2 + c3;
    cout << "c4 = c2 + c3, c4 = " << c4 << endl;
}

int main() {
    test();
}

运行截图：

启发：

1.实验三中的代码直接引用了c++中自带的complex库，自带一些关于复数的操作。

2.有的时候可以适当引用一些库，以减少代码量。

4.实验任务四：

Fraction.h:

#pragma once
#include <iostream>
class Fraction
{
private:
    int up, down;
  /*  int gcb(int a, int b)
    {
        return b == 0 ? a : gcb(b, a % b);
    }*/
public:
    Fraction(int x = 0, int y = 1);
    Fraction(const Fraction& p);
    ~Fraction();
    friend void output(const Fraction &p);
    friend Fraction add( Fraction p1,   Fraction p2);
    friend Fraction sub( Fraction p1,  Fraction p2);
    friend Fraction mul(const Fraction &p1, const Fraction &p2);
    friend Fraction div(const Fraction &p1, const Fraction &p2);
    int get_up();
    int get_down();
    Fraction negative();
    static std::string doc;
}

Fraction.cpp:

#include "Fraction.h"
#include <iostream>
#include <algorithm>
using namespace std;

int ogcd(int a, int b)
{
    if (a < b)
    {
        int c = b;
        b = a;
        a = c;
    }
    int r = a % b;
    while (r != 0)
    {
        a = b;
        b = r;
        r = a % b;
    }
    return b;
}
int igcd(int a, int b)
{
    int sum1 = ogcd(a, b);
    return (a / sum1) * (b / sum1) * sum1;
}
std::string Fraction::doc = "Fraction类测试:\nFraction类 v 0.01版.\n目前仅支持分数对象的构造、输出、加/减/乘/除运算.";
Fraction::Fraction(int x, int y)  {
  /*if (x < 0)
    {
        int a = -x;
        int b = ogcd(a, y);
        x = x / b;
        y = y / b;
    }
    else if (y < 0)
    {
        int a = -y;
        int b = ogcd(x, a);
        y = y / b;
        x = x / b;
    }
    else
    {
        int a = y;
        y = y / ogcd(x, a);
        x = x / ogcd(x, a);
    }*/
    up = x;///ogcd(abs(up), abs(down));
    down = y;///ogcd(abs(up), abs(down));
}
Fraction::Fraction(const Fraction& p) :up{ p.up }, down{ p.down } {}
Fraction::~Fraction() {}
void output(const Fraction& p)
{
    if (p.down == 0)
    {
        cout << "分母不能为0";
        return;
    }
    if (p.up == 0)
    {
        cout << "0";
        return;
    }
    if (p.down == 1)
    {
        cout << p.up;
        return;
    }
    int sum;
    if (p.up < 0)
    {
        sum = ogcd(-p.up, p.down);
        cout << "-" << -p.up / sum << "/" << p.down / sum;
        return;
    }
    else if (p.down < 0)
    {
        sum = ogcd(p.up, -p.down);
        cout << "-" << p.up / sum << "/" << -p.down / sum;
        return;
    }
    else
    {
        sum = ogcd(p.up, p.down);
        cout << p.up / sum << "/" << p.down / sum;
        return;
    }
}
Fraction add(Fraction p1, Fraction p2)
{
    if (p1.down < 0)
    {
        p1.up = -p1.up;
        p1.down = -p1.down;
    }
    if (p2.down < 0)
    {
        p2.up = -p2.up;
        p2.down = -p2.down;
    }
    int sum2 = igcd(p1.down, p2.down);
    return Fraction(p1.up * (sum2 / p1.down) + p2.up * (sum2 / p2.down), sum2);
}
Fraction sub( Fraction p1,  Fraction p2)
{
    if (p1.down < 0)
    {
        p1.up = -p1.up;
        p1.down = -p1.down;
    }
    if (p2.down < 0)
    {
        p2.up = -p2.up;
        p2.down = -p2.down;
    }
    int sum2 = igcd(p1.down, p2.down);
    return Fraction(p1.up * (sum2 / p1.down) - p2.up * (sum2 / p2.down), sum2);
}
Fraction mul(const Fraction& p1, const Fraction& p2)
{
    return Fraction(p1.up * p2.up, p1.down * p2.down);
}
Fraction div(const Fraction& p1, const Fraction& p2)
{
    return Fraction(p1.up * p2.down, p1.down * p2.up);
}

int Fraction::get_up()
{
        return up/ogcd(abs(up),abs(down));
    
 
}
int Fraction::get_down()
{
        return down/ ogcd(abs(up), abs(down));
  
}
Fraction Fraction::negative()
{
    return Fraction(-up,down);
}

task4.cpp:

#include "Fraction.h"
#include <iostream>
using std::cout;
using std::endl;


void test1() {
    cout << "Fraction类测试: " << endl;
    cout << Fraction::doc << endl << endl;

    Fraction f1(5);
    Fraction f2(3, -4), f3(-18, 12);
    Fraction f4(f3);
    cout << "f1 = "; output(f1); cout << endl;
    cout << "f2 = "; output(f2); cout << endl;
    cout << "f3 = "; output(f3); cout << endl;
    cout << "f4 = "; output(f4); cout << endl;

    Fraction f5(f4.negative());
    cout << "f5 = "; output(f5); cout << endl;
    cout << "f5.get_up() = " << f5.get_up() << ", f5.get_down() = " << f5.get_down() << endl;

    cout << "f1 + f2 = "; output(add(f1, f2)); cout << endl;
    cout << "f1 - f2 = "; output(sub(f1, f2)); cout << endl;
    cout << "f1 * f2 = "; output(mul(f1, f2)); cout << endl;
    cout << "f1 / f2 = "; output(div(f1, f2)); cout << endl;
    cout << "f4 + f5 = "; output(add(f4, f5)); cout << endl;
}

void test2() {
    Fraction f6(42, 55), f7(0, 3);
    cout << "f6 = "; output(f6); cout << endl;
    cout << "f7 = "; output(f7); cout << endl;
    cout << "f6 / f7 = "; output(div(f6, f7)); cout << endl;
}

int main() {
    cout << "测试1: Fraction类基础功能测试\n";
    test1();

    cout << "\n测试2: 分母为0测试: \n";
    test2();
}

运行截图：

5.实验任务五：

account.h:

#ifndef __ACCOUNT_H__
#define __ACCOUNT_H__
class SavingAccount
{
private:
    int id;
    double balance;
    double rate;
    int lastDate;
    double accumulation;
    static double total;
    void record(int date, double amount);
    double accumulate(int date) const {
        return accumulation + balance * (date - lastDate);
    }
public:
    SavingAccount(int date, int id, double rate);
    int getId()const { return id; }
    double getBalance()const { return balance; }
    double getRate() const { return rate; }
    static double getTotal() { return total; }
    void deposit(int date, double amount);
    void withdraw(int date, double amount);
    void settle(int date);
    void show() const;
};



#endif

account.cpp:

#include "account.h"
#include <cmath>
#include <iostream>
using namespace std;
double SavingAccount::total = 0;
SavingAccount::SavingAccount(int date, int id, double rate) :id(id), balance(0), rate(rate), lastDate(date), accumulation(0)
{
    cout << date << "\t#" << id << "is created" << endl;
}
void SavingAccount::record(int date, double amount)
{
    accumulation = accumulate(date);
    lastDate = date;
    amount = floor(amount * 100 + 0.5) / 100;    //保留小数点后两位
    balance += amount;
    total += amount;
    cout << date << "\t#" << id << "\t"<<amount<<"\t"<<balance << endl;
}
void SavingAccount::deposit(int date, double amount)
{
    record(date, amount);
}
void SavingAccount::withdraw(int date, double amount)
{
    if (amount > getBalance())
    {
        cout << "Error: not enough money" << endl;
    }
    else
    {
        record(date, -amount);
    }
}
void  SavingAccount::settle(int date)
{
    double interest = accumulate(date) * rate / 365;
    if (interest != 0)
    {
        record(date, interest);
    }
    accumulation = 0;
}
void SavingAccount::show() const 
{
    cout << "#" << id << "\tBalance: " << balance;
}

5_11.cpp:

#include "account.h"
#include <iostream>
using namespace std;
int main()
{
    SavingAccount sa0(1, 21325302, 0.015);
    SavingAccount sa1(1, 58320212, 0.015);
    sa0.deposit(5, 5000);
    sa1.deposit(25, 10000);
    sa0.deposit(45, 5500);
    sa1.withdraw(60, 4000);
    sa0.settle(90);
    sa1.settle(90);
    sa0.show(); cout << endl;
    sa1.show(); cout << endl;
    cout << "Tatal: " << SavingAccount::getTotal() << endl;
    return 0;
}