实验2 类和对象_基础编程1

实验一

t.h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();

t.cpp源码：

// 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源码：

#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();
}

问题一：

需要在t.h中对func()进行声明，否则t.cpp和task1.cpp找不到func()的声明。

问题二：

T(int x=0,int y=0);  是创建一个T类对象，并且初始化x,y。 调用时机：每当一个T类对象被创建时，此构造函数就会被调用

T(const T &t);  通过已有的对象T把T中的数据复制传给新对象t。调用时机：当一个对象通过另一个对象初始化时，会被调用

T(T &&t); 移动构造函数用于通过移动语义从另一个对象创建新对象。 调用时机：当对象通过 std::move 或其他移动语义传递时，移动构造函数会被调用

~T();析构函数在对象生命周期结束时被调用。 调用时机：当一个对象超出作用域或被显式删除时，析构函数会被调用

问题三：

不能正确编译运行

实验二

t.h源码：

#pragma once
#include<string>
class Complex
{
public:
    Complex(double a = 0, double b = 0) : real(a), imag(b) {}
    Complex(const Complex& c1) : real(c1.real), imag(c1.imag) {}
    ~Complex() = default;
    void add(const Complex& c1) {
        real += c1.real;
        imag += c1.imag;
    }
    double get_real() const { return real; }
    double get_imag() const { return imag; }  
    static std::string doc;
    friend bool is_equal(const Complex& c1, const Complex& c2);
    friend bool is_not_equal(const Complex& c1, const Complex& c2);
    friend Complex add(const Complex& c1, const Complex& c2);
    friend double abs(const Complex& c1);
    friend void output(const Complex& c);
private:
    double real;
    double imag;
};

t.cpp源码：

#include "t.h"
#include<iostream>
#include<string>
#include<cmath>
using std::cout;
using std::endl;
using std::string;
string Complex::doc = "This is a Complex Number class";
void output(const Complex& c) {
    if (c.imag == 0)
        cout << c.real;
    else if (c.imag < 0)
        cout << c.real << " - " << abs(c.imag) << "i";
    else
        cout << c.real << " + " << abs(c.imag) << "i";
}
Complex add(const Complex& c1, const Complex& c2) {
    return Complex(c1.real + c2.real, c1.imag + c2.imag);
}
bool is_equal(const Complex& c1, const Complex& c2) {
    return (c1.real == c2.real && c1.imag == c2.imag);
}
bool is_not_equal(const Complex& c1, const Complex& c2) {
    return !is_equal(c1, c2);
}
double abs(const Complex& c) {
    return sqrt(c.real * c.real + c.imag * c.imag);
}

task2.cpp源码：

#include"t.h"
#include<iostream>
using std::cout;
using std::endl;
using namespace std;
void test() {
    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();
    return 0;
}

实验三

#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();
}

提供了默认构造函数，带参构造函数，复制构造函数，取模运算，访问实部虚部，求和运算，加法运算符重载，判断两个复数是否相等

对比任务2：

1.不需要进行类和友元函数的构造和说明 2.用标准库降低了代码的复杂度，减少出错

实验四

t.h源码：

#pragma once
#include<string>
class Fraction {
public:
    Fraction(int a = 0, int b = 1) : up(a), down(b) {
        int k = gcd(up, down);
        up /= k;
        down /= k;
    }
    Fraction(const Fraction& f) : up(f.up), down(f.down) {
        int k = gcd(up, down);
        up /= k;
        down /= k;
    }
    ~Fraction() = default;

    int get_up() const { return up; }
    int get_down() const { return down; }

    void negative() {
        up = -up;
    }

    static int gcd(int a, int b) {
        while (b != 0) {
            int r = b;
            b = a % b;
            a = r;
        }
        return (a == 0 ? 1 : a);
    }

    static std::string doc;

    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);

private:
    int up;
    int down;
};

t.cpp源码：

#include "task2.h"
#include<iostream>
#include<string>
#include<cmath>
#include <stdexcept>
using std::cout;
using std::endl;
using std::string;
std::string Fraction::doc = "Fraction类用于表示和操作分数。";

void output(const Fraction& f) {
    if (f.up == 0) {
        cout << f.up;
        return;
    }
    if (f.down == 1) {
        cout << f.up;
        return;
    }
    int c = Fraction::gcd(std::abs(f.up), std::abs(f.down));
    int a = f.up / c;
    int b = f.down / c;
    if (b < 0) {
        a = -a;
        b = -b;
    }

    if (a < 0) {
        cout << "-";
        a = -a;
    }

    cout << a << "/" << b;
}

Fraction add(const Fraction& f1, const Fraction& f2) {
    Fraction temp(0, 0);
    temp.down = f1.down * f2.down;
    temp.up = f1.up * f2.down + f2.up * f1.down;
    int k = Fraction::gcd(temp.up, temp.down);
    temp.up /= k;
    temp.down /= k;
    return temp;
}

Fraction sub(const Fraction& f1, const Fraction& f2) {
    Fraction temp = f1;
    temp.negative();
    return add(temp, f2);
}

Fraction mul(const Fraction& f1, const Fraction& f2) {
    Fraction temp(f1.up * f2.up, f1.down * f2.down);
    int k = Fraction::gcd(temp.up, temp.down);
    temp.up /= k;
    temp.down /= k;
    return temp;
}

Fraction div(const Fraction& f1, const Fraction& f2) {
    if (f2.up == 0) {
        throw std::runtime_error("分母不能为0");
    }
    Fraction temp(f1.up * f2.down, f1.down * f2.up);
    int k = Fraction::gcd(temp.up, temp.down);
    temp.up /= k;
    temp.down /= k;
    return temp;
}

#include"task2.h"
#include<iostream>
using std::cout;
using std::endl;
using namespace std;

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;
    f5.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;
    try {
        cout << "f6 / f7 = "; output(div(f6, f7)); cout << endl;
    }
    catch (const std::runtime_error& e) {
        cout << e.what() << 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();
}

实验五

t.h源码：

#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 desposit(int date, double amount);
    void withdraw(int date, double amount);
    void settle(int date);
    void show() const;
};
#endif//_ _ACCOUNT_H _ _

t.cpp源码：

#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::desposit(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;
}

5_11.cpp源码：

#include"account.h"
#include<iostream>
using namespace std;
int main() {
    SavingsAccount sa0(1, 21325302, 0.015);
    SavingsAccount sa1(1, 58320212, 0.015);
    sa0.desposit(5, 5000);
    sa1.desposit(25,10000);
    sa0.desposit(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;
}