实验2

实验任务1：

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;
}

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();
};

// 普通函数声明
void func();

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();
}

 Q1:可以去掉line36

Q2:默认构造函数：在没有提供任何参数的情况下创建对象能否正确编译运行时调用的构造函数
拷贝构造函数：使用另一个对象来初始化新对象时，将对象作为参数传递给函数时，从函数返回对象时
移动构造函数：从临时对象（右值）转移资源
委托构造函数：一个构造函数调用同一个类的另一个构造函数
析构函数：在对象生命周期结束时调用，用于释放对象占用的资源；在对象离开其作用域时，显式删除动态分配的对象时，程序结束时调用

Q3:能正确编译运行

实验任务2：

#ifndef COMPLEX_H  

#define COMPLEX_H  



#include <iostream>  

#include <cmath>  

#include <string>  



class Complex {  

public:  

    static const std::string doc;   



private:  

    double real; 

    double imag;  



public:  

     

    Complex();  

    Complex(double r);  

    Complex(double r, double i); 

    Complex(const Complex &c);  



   

    double get_real() const;  

    double get_imag() const;  

    Complex add(const Complex &c) const;  

    bool is_equal(const Complex &c) const;  

    bool is_not_equal(const Complex &c) const;  

    void output() const;  

    double abs() const;  

};  



#endif 



#include "Complex.h"  

const std::string Complex::doc = "a simplified complex class";    

Complex::Complex() : real(0), imag(0) {}   

Complex::Complex(double r) : real(r), imag(0) {}  

Complex::Complex(double r, double i) : real(r), imag(i) {}   

Complex::Complex(const Complex &c) : real(c.real), imag(c.imag) {}  

double Complex::get_real() const {  

    return real;  

}  

double Complex::get_imag() const {  

    return imag;  

}  

Complex Complex::add(const Complex &c) const {  

    return Complex(this->real + c.real, this->imag + c.imag);  

}  

bool Complex::is_equal(const Complex &c) const {  

    return (real == c.real && imag == c.imag);  

}  

bool Complex::is_not_equal(const Complex &c) const {  

    return !is_equal(c);  

}  

void Complex::output() const {  

    std::cout << real << (imag >= 0 ? " + " : " - ") << fabs(imag) << "i";  

}  

double Complex::abs() const {  

    return std::sqrt(real * real + imag * imag);  

}



#include <iostream>  

#include "Complex.h"  



using std::cout;  

using std::endl;  



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 = "; c1.output(); cout << endl;  

    cout << "c2 = "; c2.output(); cout << endl;  

    cout << "c3 = "; c3.output(); cout << endl;  

    cout << "c4 = "; c4.output(); 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) = " << c2.abs() << endl;  

    c1 = c1.add(c2);  

    cout << "c1 += c2, c1 = "; c1.output(); cout << endl;  

    cout << "c1 == c2 : " << std::boolalpha << c1.is_equal(c2) << endl;  

    cout << "c1 != c3 : " << std::boolalpha << c1.is_not_equal(c3) << endl;  

    c4 = c2.add(c3);  

    cout << "c4 = c2 + c3, c4 = "; c4.output(); cout << endl;  

}  



int main() {  

    test();  

    return 0;  

}

 实验任务3：

#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();
}

 实验任务4：

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();
}

Fraction.h

#pragma once
#include <iostream>
class Fraction
{
private:
    int up, down;
 
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)  {
 
    up = x;
    down = y;
}
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);
}

 实验任务5：

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;
}

 结论：

1.学习了如何使用访问修饰符（public、private、protected）进行数据保护，同时也探索了静态成员的使用，以实现数据的共享。

2.通过多文件结构的组织，体会到了良好代码结构对于程序可读性和维护性的重要性，锻炼了他们在项目中分离接口与实现的能力。

3.增强了对类设计的思考能力，能够更灵活地解决实际问题，例如在银行账户管理的实例中实现基本功能。