实验2

task 1.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;
}

#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();

#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();
}

 

运行结果截图：

 

 

task2.cpp

 

#pragma once

#include<string>

class Complex
{
public:
    Complex(double = 0, double = 0);
    Complex(const Complex&);
    double get_real() const;
    double get_imag() const;
    void add(const Complex&);
    static  std::string doc;

private:
    double real;
    double imag;

    friend Complex& add(const Complex&, const Complex&);
    friend bool is_equal(const Complex&, const Complex&);
    friend bool is_not_equal(const Complex&, const Complex&);
    friend double abs(const Complex&);
    friend void output(const Complex&);
};

Complex& add(const Complex&, const Complex&);
bool is_equal(const Complex&, const Complex&);
bool is_not_equal(const Complex&, const Complex&);
double abs(const Complex&);
void output(const Complex&);

#include"Complex.h"

#include<iostream>
#include<string>
#include<cmath>
using std::cout;
using std::endl;
std::string  Complex::doc = "a simplified complex class";
Complex::Complex(double a, double b) :real{ a }, imag{ b } {}
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;
}
void Complex::add(const Complex& c)
{
    real += c.real;
    imag += c.imag;
}
Complex& add(const Complex& c1, const Complex& c2)
{
    Complex c3(c1.real + c2.real, c1.imag + c2.imag);
    return c3;
}
bool is_equal(const Complex& c1, const Complex& c2)
{
    if (c1.real == c2.real && c1.imag == c2.imag)
        return true;
    else
        return false;
}
bool is_not_equal(const Complex& c1, const Complex& c2)
{
    if (c1.real != c2.real || c1.imag != c2.imag)
        return true;
    else
        return false;
}
double abs(const Complex& c)
{
    double a = sqrt(pow(c.real, 2) + pow(c.imag, 2));
    return a;
}
void output(const Complex& c)
{
    cout << c.real << " + " << c.imag << "i" << endl;
}

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

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();
}

 

运行结果截图：

 

 

task3.cpp

 

#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();
}

 适当的使用标准库complex模板类，使代码更简洁，因为只需要包含头文件和测试代码。可以直接使用标准库提供的接口，无需手动编写和调试运算函数和输出函数。

运行结果截图：

 

 

task4.cpp

 

#pragma once
#include<string>

class Fraction
{
public:
    static std::string doc;
    Fraction(int = 0, int = 1);
    Fraction(Fraction&);
    int get_up();
    int get_down();
    Fraction& negative();

private:
    int up;
    int down;

    friend void output(Fraction&);
    friend Fraction& add(Fraction&, Fraction&);
    friend Fraction& sub(Fraction&, Fraction&);
    friend Fraction& mul(Fraction&, Fraction&);
    friend Fraction& div(Fraction&, Fraction&);
};
int fun(int, int);//求最大公因数
void output(Fraction&);
Fraction& add(Fraction&, Fraction&);
Fraction& sub(Fraction&, Fraction&);
Fraction& mul(Fraction&, Fraction&);
Fraction& div(Fraction&, Fraction&);

#include"Fraction.h"
#include<iostream>
#include<string>
#include<cmath>
using std::cout;
using std::endl;
int fun(int a, int b)
{
    if (a == b)
        return a;
    else if (a > b)
    {
        while (b)
        {
            int t = a % b;
            a = b; b = t;
        }
        return a;
    }
    else
    {
        while (a)
        {
            int t = b % a;
            b = a; a = t;
        }
        return b;
    }
}
std::string Fraction::doc = "Fraction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 a, int b) :up{ abs(a) }, down{ abs(b) }//这样在创造时分母一定大于0，负号只会在分子上
{
    if (a * b < 0)
        up *= -1;
}
Fraction::Fraction(Fraction& c) :up{ abs(c.up) }, down(abs(c.down))
{
    if (c.up * c.down < 0)
        up *= -1;
}
int Fraction::get_up()
{
    return up;
}
int Fraction::get_down()
{
    return down;
}
Fraction& Fraction::negative()
{
    Fraction c(-up, down);
    return c;
}
void output(Fraction& c)
{
    if (c.down == 0)
    {
        cout << "分母不能为0" << endl;
    }
    else if (c.up == 0 || c.down == 1)//这种情况只有分子有用
    {
        cout << c.up << endl;
    }
    else
    {
        int t = fun(abs(c.up), abs(c.down));
        int up = c.up, down = c.down;
        if (t != 1)
        {
            up /= t; down /= t;
        }
        cout << up << "/" << down << endl;
    }
}
Fraction& add(Fraction& c1, Fraction& c2)
{
    int down = c1.down * c2.down;
    int up = c1.up * c2.down + c2.up * c1.down;
    Fraction c3(up, down);//化简什么的就交给output吧！
    return c3;
}
Fraction& sub(Fraction& c1, Fraction& c2)
{
    int down = c1.down * c2.down;
    int up = c1.up * c2.down - c2.up * c1.down;
    Fraction c3(up, down);
    return c3;
}
Fraction& mul(Fraction& c1, Fraction& c2)
{
    int down = c1.down * c2.down;
    int up = c1.up * c2.up;
    Fraction c3(up, down);
    return c3;
}
Fraction& div(Fraction& c1, Fraction& c2)
{
    int down = c1.down * c2.up;
    int up = c1.up * c2.down;
    Fraction c3(up, down);
    return c3;
}

#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();
}

 

运行结果截图：

 

 

task5.cpp

 

#pragma once
class SavingsAccount {
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:
    SavingsAccount(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;
};

#include"account.h"
#include<cmath>
#include<iostream>
using namespace std;
double SavingsAccount::total = 0;


SavingsAccount::SavingsAccount(int date, int id, double rate) :id(id), balance(0), rate(rate), lastDate(date), accumulation(0)
{
    cout << date << "\t#" << id << " is created" << endl;
}

void SavingsAccount::record(int date, double amount)
{
    accumulation = accumulate(date);
    lastDate = date;
    amount = floor(amount * 100 + 0.5) / 100;
    balance += amount;
    total += amount;
    cout << date << "\t#" << id << "\t" << amount << "\t" << balance << endl;
}
void SavingsAccount::deposit(int date, double amount) {
    record(date, amount);
}
void SavingsAccount::withdraw(int date, double amount) {
    if (amount > getBalance())
        cout << "Error:not enough money" << endl;
    else
    {
        record(date, -amount);
    }
}
void SavingsAccount::settle(int date) {
    double interest = accumulate(date) * rate / 365;
    if (interest != 0)
        record(date, interest);
    accumulation = 0;
}
void SavingsAccount::show()const {
    cout << "#" << id << "\tBalance:" << balance;
}

#include"account.h"
#include<iostream>
using namespace std;
int main() {
    SavingsAccount sa0(1, 21325302, 0.015);
    SavingsAccount 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 << "Total: " << SavingsAccount::getTotal() << endl;
    return 0;
}

体会：

类通过私有成员变量和公有成员函数实现了封装。外界只能通过公有成员函数来访问和操作账户信息，保证了数据的安全性和完整性。程序中使用了静态成员变量来记录总账户数，这是数据共享。同时，通过类的封装和访问权限控制，保护了账户信息不被非法访问和修改。对银行账户进行了抽象，使得代码更加简洁、易于理解和维护。

运行结果截图：