实验2 类和对象_基础编程1

实验任务1：

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();

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();
}

问题1：

不能，因为编译器找不到func函数的定义。

问题2：

1.普通构造函数：功能是用于创建对象时初始化对象的成员变量。时机是对象被创建时。

2.复制构造函数：功能是用于创建一个新对象，作为已有对象的副本。时机是使用已存在的对象初始化另一个对象时。

3.移动构造函数：功能是用于移动构造对象，适用于临时对象。时机是对象被移动时，通常在返回临时对象、使用std::move函数时。

4.析构函数：时机是对象被销毁时。

问题3：不能。

 

实验任务2：

complex.h

#pragma once
#include <iostream>
#include <cmath>

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;
    void add(const Complex &c);

    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.cpp

#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;
}

void Complex::add(const Complex &c) {
    real += c.real;
    imag += c.imag;
}

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 (c1.real != c2.real) || (c1.imag != c2.imag);
}

void output(const Complex &c) {
    std::cout << c.real << (c.imag >= 0 ? " + " : " - ") << std::abs(c.imag) << "i";
}

double abs(const Complex &c) {
    return std::sqrt(c.real * c.real + c.imag * c.imag);
}

task2.cpp

#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;
}

void Complex::add(const Complex &c) {
    real += c.real;
    imag += c.imag;
}

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 (c1.real != c2.real) || (c1.imag != c2.imag);
}

void output(const Complex &c) {
    std::cout << c.real << (c.imag >= 0 ? " + " : " - ") << std::abs(c.imag) << "i";
}

double abs(const Complex &c) {
    return std::sqrt(c.real * c.real + c.imag * c.imag);
}

 

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();
}

对比任务2：

1.可以调用成员函数，直接访问复数的实部和虚部。可以直接使用cout进行输出。可以直接对复数进行相加，取模运算，判断是否相等。

2.掌握标准库模板类的使用可以简化程序。

 

实验任务4：

Fraction.h

#pragma once
#include<iostream>
#include<string>

using namespace std;

class Fraction{
    public:
        Fraction(int x,int y = 1);
        Fraction(const Fraction &f);
        ~Fraction();
        int get_up() const;
        int get_down() const;
        Fraction negative();

    private:
        int up;
        int down;

    public:
        static const 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);

};

Fraction.h

#include "Fraction.h"
#include <iostream>
#include <string>
#include<math.h>
#include<cmath>

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

  const 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 x,int y){
      int a = abs(x),b = y;
      while (b!=0) {
            int temp =b;
            b = a % b;
            a =temp;
        }
    up = x /a;
    down = y/a;
  }

  Fraction::Fraction(const Fraction &f): up{f.get_up()},down{f.get_down()}{
  }

  Fraction::~Fraction(){
  }

  int Fraction::get_up() const{
      return up;
  }

  int Fraction::get_down() const{
      return down;
  }

  Fraction Fraction::negative(){
      return Fraction((-1)*up,down);
  }

  void output(const Fraction &f){
      if(f.get_down() == 0){
          cout << "分母不能为0";
          return;
      }
      if(f.get_down() == 1){
          cout << f.get_up();
      }else{
          cout << f.get_up() << "/" << f.get_down();
      }
  }

  Fraction add(const Fraction &f1,const Fraction &f2){
      int gcd = f1.get_down();
    int temp_b = f2.get_down();

    while (temp_b != 0) {
        int temp = temp_b;
        temp_b = gcd % temp_b;
        gcd = temp;
    }

    int minMax = std::abs(f1.get_down()*f2.get_down()) / gcd;

    int i = minMax/f1.get_down();
    int j = minMax/f2.get_down();

  return Fraction(i*f1.get_up() + j*f2.get_up(),minMax);
  }




  Fraction sub(const Fraction &f1,const Fraction &f2){
      int gcd = f1.get_down();
    int temp_b = f2.get_down();

    while (temp_b != 0) {
        int temp = temp_b;
        temp_b = gcd % temp_b;
        gcd = temp;
    }

    int minMax = std::abs(f1.get_down()*f2.get_down()) / gcd;
      int i,j;

  i = minMax/f1.get_down();
  j = minMax/f2.get_down();

  return Fraction(i*f1.get_up() - j*f2.get_up(),minMax);
  }




  Fraction mul(const Fraction &f1,const Fraction &f2){
      return Fraction(f1.get_up()*f2.get_up(),f1.get_down()*f2.get_down());
  }

  Fraction div(const Fraction &f1,const Fraction &f2){
      return Fraction(f1.get_up()*f2.get_down(),f1.get_down()*f2.get_up());
  }

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();
}

 

实验任务5：

account.h

#pragma once

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;

};

account.cpp

#include"account.h"
#include<iostream>
#include<cmath>

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;
    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;
}

task5

#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 << "Total: " << SavingAccount::getTotal() << endl;

}

合理