OOP实验二

任务1

源码：

#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();

// 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;
}

#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();
}

 

结果：

问：t.h中，普通函数 func 作为类X的友元，在类的内部声明了友元关系。在类外部，去掉

line36，重新编译，是否能正确运行。如果能，回答说明可以去掉line36。如果不能，以截图

形式给出编译报错信息，分析可能的原因。

答：不能

 在类内部的声明不会提醒main函数普通函数func的存在。

问：t.h中，line9-12给出了各种构造函数、析构函数。总结各种构造函数的功能，以及它们与析

构函数的调用时机。

答：

普通构造函数：通过数值创建对象实例。

复制构造函数：利用一个已知的对象实例给新实例赋值。

移动构造函数：在处理临时对象是时提高效率。

析构函数：释放实例占用的内存。

问：t.cpp中，line13-15，调整到t.h，重新编译，程序能否正确编译运行。

答：不能。

任务2

源码：

 

//.h:
#pragma once

#include<iostream>
#include<cmath>

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

void test();

class Complex {
private:
    double real, imag;
public:
    static std::string doc;
    Complex(double r = 0, double i = 0) :real{ r }, imag{ i } {}
    Complex(const Complex& c) :real{ c.get_real() }, imag{ c.get_imag() } {}
    double get_real() const {
        return real;
    }
    double get_imag() const {
        return imag;
    }
    void add(const Complex c) {
        real += c.get_real();
        imag += c.get_imag();
    }
    friend Complex add(const Complex c1, const Complex c2);
    friend bool is_equal(const Complex& c1, const Complex& c2);
    friend bool is_not_equal(const Complex& c1, const Complex& c2);
    friend void output(const Complex& c);
    friend double abs(const Complex& c);
};

Complex add(const Complex c1, const Complex c2);
bool is_equal(const Complex& c1, const Complex& c2);
bool is_not_equal(const Complex& c1, const Complex& c2);
void output(const Complex& c);
double abs(const Complex& c);

//.cpp:
#include"Complex.h"

std::string Complex::doc = "a simple complex class";

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;
}
Complex add(const Complex c1,const Complex c2) {
    Complex c3;
    c3.add(c2);
    c3.add(c1);
    return c3;
}
bool is_equal(const Complex& c1, const Complex& c2) {
    if (c1.get_imag() == c2.get_imag() && c1.get_real() == c2.get_real())
    {
        return true;
    }
    else
    {
        return false;
    }
}

bool is_not_equal(const Complex& c1, const Complex& c2) {
    if (c1.get_imag() == c2.get_imag() && c1.get_real() == c2.get_real())
    {
        return false;
    }
    else
    {
        return true;
    }
}

void output(const Complex& c) {
    if (c.get_imag() >= 0) {
        cout << c.get_real() << '+' << c.get_imag() << 'i' << endl;
    }
    else {
        cout << c.get_real() << '-' << abs(c.get_imag()) << 'i' << endl;
    }
}
double abs(const Complex& c) {
    return sqrt(c.get_imag() * c.get_imag() + c.get_real() * c.get_real());

}

//.main:
#include"Complex.h"
int main() {
    test();
}

 

结果：

 

 

任务3

源码：

#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();
}

 

结果：

 

任务4

源码：

 

//.h
#pragma once
#include <iostream>

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

int measure(int x, int y);
class Fraction {
private:
    int up;
    int down;
public:
    static std::string doc;
    Fraction(int u, int d = 1){
        int mea = measure(u, d);
        up = u / mea;
        down = d / mea;
        if (down < 0)
        {
            down = -down;
            up = -up;
        }
    }
    int get_up() const {
        return up;
    }
    int get_down() const {
        return down;
    }
    Fraction negative() {
        Fraction f(-up, down);
        return f;
    }
    friend void output(const Fraction& f);
    friend Fraction add(const Fraction f1, const Fraction f2);
    friend Fraction sub(const Fraction f1, const Fraction f2);
    friend Fraction mul(const Fraction f1, const Fraction f2);
    friend Fraction div(const Fraction f1, const Fraction f2);
};

Fraction add(const Fraction f1, const Fraction f2);
Fraction sub(const Fraction f1, const Fraction f2);
Fraction mul(const Fraction f1, const Fraction f2);
Fraction div(const Fraction f1, const Fraction f2);
void output(const Fraction& f);

//.cpp
#include "Fraction.h"

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\n";
Fraction add(const Fraction f1, const Fraction f2) {
    int up1, up2, down1, down2, up, down;
    up1 = f1.up;
    up2 = f2.up;
    down1 = f1.down;
    down2 = f2.down;
    up = up1 * down2 + up2 * down1;
    down = down1 + down2;
    int mea = measure(up, down);
    Fraction f(up / mea, down / mea);
    return f;
}
Fraction sub(const Fraction f1, const Fraction f2) {
    int up1, up2, down1, down2, up, down;
    up1 = f1.up;
    up2 = f2.up;
    down1 = f1.down;
    down2 = f2.down;
    up = up1 * down2 - up2 * down1;
    down = down1 + down2;
    int mea = measure(up, down);
    Fraction f(up / mea, down / mea);
    return f;
}
Fraction mul(const Fraction f1, const Fraction f2) {
    int up1, up2, down1, down2, up, down;
    up1 = f1.up;
    up2 = f2.up;
    down1 = f1.down;
    down2 = f2.down;
    up = up1 * up2;
    down = down1 * down2;
    int mea = measure(up, down);
    Fraction f(up / mea, down / mea);
    return f;
}
Fraction div(const Fraction f1, const Fraction f2) {
    if (f2.up == 0)
    {
        Fraction error(0, 0);
        return error;
    }
    int up1, up2, down1, down2, up, down;
    up1 = f1.up;
    up2 = f2.up;
    down1 = f1.down;
    down2 = f2.down;
    up = up1 * down2;
    down = up2 * down1;
    int mea = measure(up, down);
    Fraction f(up / mea, down / mea);
    return f;
}
void output(const Fraction& f) {
    if (f.down != 0)
    {
        if (f.up == 0 || f.down == 1)
        {
            cout << f.up;
        }
        else
        {
            cout << f.up << "/" << f.down;
        }
    }
    else 
    {
        cout << "分母不能为0";
    }
}
int measure(int x, int y)
{
    if (y == 0)
    {
        return 1;
    }
    int z = y;
    while (x % y != 0)
    {
        z = x % y;
        x = y;
        y = z;
    }
    return z;
}

//.main
#include"Fraction.h"

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();
}

 

结果：

 

任务5

源码：

//.h
#ifndef __ACCOUNT_H__
#define __ACCOUNT_H__
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;
};
#endif // !__ACCOUNT__

//.cpp
#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;
}

//.main
#include"account.h"
#include<iostream>
using namespace std;
int main() {
    SavingsAccount sa0(1, 2132502, 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;
}

 

结果：