实验2 类和对象_基础编程1 - Haruto

Task1

t.h

 1 #pragma once
 2 
 3 #include <string>
 4 
 5 // 类T: 声明
 6 class T {
 7     // 对象属性、方法
 8 public:
 9     T(int x = 0, int y = 0); // 普通构造函数
10     T(const T& t); // 复制构造函数
11     T(T&& t); // 移动构造函数
12     ~T(); // 析构函数
13 
14     void adjust(int ratio); // 按系数成倍调整数据
15     void display() const; // 以(m1, m2)形式显示T类对象信息
16 
17 private:
18     int m1, m2;
19 
20     // 类属性、方法
21 public:
22     static int get_cnt(); // 显示当前T类对象总数
23 
24 public:
25     static const std::string doc; // 类T的描述信息
26     static const int max_cnt; // 类T对象上限
27 
28 private:
29     static int cnt; // 当前T类对象数目
30 
31     // 类T友元函数声明
32     friend void func();
33 };
34 
35 // 普通函数声明
36 void func();

View Code

t.cpp

 1 // 类T: 实现
 2 // 普通函数实现
 3 
 4 #include "t.h"
 5 #include <iostream>
 6 #include <string>
 7 
 8 using std::cout;
 9 using std::endl;
10 using std::string;
11 
12 // static成员数据类外初始化
13 const std::string T::doc{ "a simple class sample" };
14 const int T::max_cnt = 999;
15 int T::cnt = 0;
16 
17 
18 // 对象方法
19 T::T(int x, int y) : m1{ x }, m2{ y } {
20     ++cnt;
21     cout << "T constructor called.\n";
22 }
23 
24 T::T(const T& t) : m1{ t.m1 }, m2{ t.m2 } {
25     ++cnt;
26     cout << "T copy constructor called.\n";
27 }
28 
29 T::T(T&& t) : m1{ t.m1 }, m2{ t.m2 } {
30     ++cnt;
31     cout << "T move constructor called.\n";
32 }
33 
34 T::~T() {
35     --cnt;
36     cout << "T destructor called.\n";
37 }
38 
39 void T::adjust(int ratio) {
40     m1 *= ratio;
41     m2 *= ratio;
42 }
43 
44 void T::display() const {
45     cout << "(" << m1 << ", " << m2 << ")";
46 }
47 
48 // 类方法
49 int T::get_cnt() {
50     return cnt;
51 }
52 
53 // 友元
54 void func() {
55     T t5(42);
56     t5.m2 = 2049;
57     cout << "t5 = "; t5.display(); cout << endl;
58 }

View Code

task1.cpp

 1 #include "t.h"
 2 #include <iostream>
 3 
 4 using std::cout;
 5 using std::endl;
 6 
 7 void test();
 8 
 9 int main() {
10     test();
11     cout << "\nmain: \n";
12     cout << "T objects'current count: " << T::get_cnt() << endl;
13 }
14 
15 void test() {
16     cout << "test class T: \n";
17     cout << "T info: " << T::doc << endl;
18     cout << "T objects'max count: " << T::max_cnt << endl;
19     cout << "T objects'current count: " << T::get_cnt() << endl << endl;
20 
21 
22     T t1;
23     cout << "t1 = "; t1.display(); cout << endl;
24 
25     T t2(3, 4);
26     cout << "t2 = "; t2.display(); cout << endl;
27 
28     T t3(t2);
29     t3.adjust(2);
30     cout << "t3 = "; t3.display(); cout << endl;
31 
32     T t4(std::move(t2));
33     cout << "t3 = "; t4.display(); cout << endl;
34 
35     cout << "T objects'current count: " << T::get_cnt() << endl;
36     
37     func();
38 }

View Code

result1

问题一

在tas1.cpp中identifier "func" is undefined。

这个错误是由于 task1.cpp 文件中没有正确引用 func() 函数的声明，导致编译器无法识别 func()。虽然 func() 是 T 类的友元函数，并在 t.cpp 文件中实现，但 task1.cpp 没有包含该函数的声明要解决这个问题，需要在 t.h 文件中确保 func() 函数的声明可以被 task1.cpp 看到。虽然已经在 t.h 文件中声明了 func() 为友元函数，但还需要在全局作用域显式声明 func()，这样其他文件才能正确引用该函数。

问题二

带默认值的普通构造函数，会在初始化一个对象的时候调用，并同时赋值。

复制构造函数，在用另一个对象来初始化对象的时候调用。

移动构造函数，在需要将一个对象的资源所有权转移到另一个对象时调用。

析构函数，在对象生命期结束，销毁时调用。

问题三

被多次定义，编译错误。

Task2

Complex.h

 1 #pragma once
 2 
 3 #include<iostream>
 4 #include<cmath>
 5 
 6 using std::string;
 7 using std::cout;
 8 
 9 class Complex {
10 public:
11     Complex(double m_real = 0, double m_imag = 0);
12     Complex(const Complex& c);
13     ~Complex() = default;
14 
15     double get_real() const;
16     double get_imag() const;
17     Complex add(const Complex& c);
18 
19     friend Complex add(const Complex& c1, const Complex& c2);
20     friend bool is_equal(const Complex& c1, const Complex& c2);
21     friend bool is_not_equal(const Complex& c1, const Complex& c2);
22     friend double abs(const Complex& c);
23     friend void output(const Complex& c);
24 
25 private:
26     double real, imag;
27 
28 public:
29     static string doc;
30 };
31 
32 Complex add(const Complex& c1, const Complex& c2);
33 
34 bool is_equal(const Complex& c1, const Complex& c2);
35 
36 bool is_not_equal(const Complex& c1, const Complex& c2);
37 
38 void output(const Complex& c);
39 
40 double abs(const Complex& c);

Complex.cpp

 1 #include "Complex.h"
 2 #include <iostream>
 3 
 4 string Complex::doc{ "a simplified complex class" };
 5 
 6 Complex::Complex(double m_real, double m_imag) : real{ m_real }, imag{ m_imag } {
 7 }
 8 
 9 Complex::Complex(const Complex& c) :real{ c.real }, imag{ c.imag } {
10 }
11 
12 
13 double Complex::get_real() const {
14     return real;
15 }
16 
17 double Complex::get_imag() const {
18     return imag;
19 }
20 
21 Complex Complex::add(const Complex& c) {
22     this->real += c.real;
23     this->imag += c.imag;
24     return *this;
25 }
26 
27 
28 Complex add(const Complex& c1, const Complex& c2) {
29     Complex temp;
30     temp.real = c1.real + c2.real;
31     temp.imag = c1.imag + c2.imag;
32     return temp;
33 }
34 
35 bool is_equal(const Complex& c1, const Complex& c2) {
36     if (c1.real == c2.real && c1.imag == c2.imag)
37         return true;
38     else
39         return false;
40 }
41 
42 bool is_not_equal(const Complex& c1, const Complex& c2) {
43     if (c1.real == c2.real && c1.imag == c2.imag)
44         return false;
45     else
46         return true;
47 }
48 
49 void output(const Complex& c) {
50     cout << c.real;
51     if (c.imag < 0)
52         cout << " - " << abs(c.imag) << "i";
53     else
54         cout << " + " << c.imag << "i";
55 
56 }
57 
58 double abs(const Complex& c) {
59     double temp = c.real * c.real + c.imag * c.imag;
60     return sqrt(temp);
61 }

task2.cpp

 1 // 备用代码3
 2 #include <iostream>
 3 #include "Complex.h"
 4 
 5 using std::cout;
 6 using std::endl;
 7 using std::boolalpha;
 8 
 9 void test() {
10     cout << "类成员测试: " << endl;
11     cout << Complex::doc << endl;
12 
13     cout << endl;
14 
15     cout << "Complex对象测试: " << endl;
16     Complex c1;
17     Complex c2(3, -4);
18     const Complex c3(3.5);
19     Complex c4(c3);
20 
21     cout << "c1 = "; output(c1); cout << endl;
22     cout << "c2 = "; output(c2); cout << endl;
23     cout << "c3 = "; output(c3); cout << endl;
24     cout << "c4 = "; output(c4); cout << endl;
25     cout << "c4.real = " << c4.get_real() << ", c4.imag = " << c4.get_imag() << endl;
26 
27     cout << endl;
28 
29     cout << "复数运算测试: " << endl;
30     cout << "abs(c2) = " << abs(c2) << endl;
31     c1.add(c2);
32     cout << "c1 += c2, c1 = "; output(c1); cout << endl;
33     cout << boolalpha;
34     cout << "c1 == c2 : " << is_equal(c1, c2) << endl;
35     cout << "c1 != c3 : " << is_not_equal(c1, c3) << endl;
36     c4 = add(c2, c3);
37     cout << "c4 = c2 + c3, c4 = "; output(c4); cout << endl;
38 }
39 
40 int main() {
41     test();
42 }

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result2

Task3

task3.cpp

 1 #include <iostream>
 2 #include <complex>
 3 
 4 using std::cout;
 5 using std::endl;
 6 using std::boolalpha;
 7 using std::complex;
 8 
 9 void test() {
10     cout << "标准库模板类comple测试: " << endl;
11     complex<double> c1;
12     complex<double> c2(3, -4);
13     const complex<double> c3(3.5);
14     complex<double> c4(c3);
15 
16     cout << "c1 = " << c1 << endl;
17     cout << "c2 = " << c2 << endl;
18     cout << "c3 = " << c3 << endl;
19     cout << "c4 = " << c4 << endl;
20     cout << "c4.real = " << c4.real() << ", c4.imag = " << c4.imag() <<
21         endl;
22     cout << endl;
23 
24     cout << "复数运算测试: " << endl;
25     cout << "abs(c2) = " << abs(c2) << endl;
26     c1 += c2;
27     cout << "c1 += c2, c1 = " << c1 << endl;
28     cout << boolalpha;
29     cout << "c1 == c2 : " << (c1 == c2) << endl;
30     cout << "c1 != c3 : " << (c1 != c3) << endl;
31     c4 = c2 + c3;
32     cout << "c4 = c2 + c3, c4 = " << c4 << endl;
33 }
34 
35 int main() {
36     test();
37 }

View Code

result3

Task4

Fraction.h

 1 #pragma once
 2 
 3 #include <iostream>
 4 
 5 using std::string;
 6 using std::cout;
 7 
 8 class Fraction {
 9 public:
10     Fraction(int m_up, int m_down = 1);
11     Fraction(const Fraction& f);
12     ~Fraction() = default;
13 
14     int get_up() const;
15     int get_down() const;
16     Fraction negative() const;
17 
18 private:
19     int up, down;
20     void simp();
21 
22 public:
23     static string doc;
24 
25 public:
26     friend void output(const Fraction& f);
27     friend Fraction add(const Fraction& f1, const Fraction& f2);
28     friend Fraction sub(const Fraction& f1, const Fraction& f2);
29     friend Fraction mul(const Fraction& f1, const Fraction& f2);
30     friend Fraction div(const Fraction& f1, const Fraction& f2);
31 };
32 
33 void output(const Fraction& f);
34 
35 Fraction add(const Fraction& f1, const Fraction& f2);
36 
37 Fraction sub(const Fraction& f1, const Fraction& f2);
38 
39 Fraction mul(const Fraction& f1, const Fraction& f2);
40 
41 Fraction div(const Fraction& f1, const Fraction& f2);

Fraction.cpp

 1 #include "Fraction.h"
 2 #include <iostream>
 3 #include <cmath>
 4 
 5 using std::string;
 6 using std::cout;
 7 using std::endl;
 8 
 9 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." };
10 
11 Fraction::Fraction(int m_up, int m_down) :up{ m_up }, down{ m_down } {
12     simp();
13 }
14 
15 Fraction::Fraction(const Fraction& f) : up{ f.up }, down{ f.down } {
16     simp();
17 }
18 
19 void Fraction::simp() {
20     //调整符号
21     if (down < 0) {
22         up = -up;
23         down = -down;
24     }
25 
26     //化简操作
27     bool sign = false;
28     if (up < 0) sign = true;
29     
30     int t_up = abs(up);
31     for (int div = t_up; div > 1; div--) {
32         if (down % div == 0 && t_up % div == 0) {
33             t_up /= div;
34             down /= div;
35             if (sign)
36                 up = -t_up;
37             else
38                 up = t_up;
39             return;
40         }
41     }
42 }
43 
44 int Fraction::get_up() const {
45     return up;
46 }
47 
48 int Fraction::get_down() const {
49     return down;
50 }
51 
52 Fraction Fraction::negative() const {
53     return Fraction{ -up, down };
54 }
55 
56 void output(const Fraction& f) {
57     if (f.up == 0)
58         cout << 0;
59     else if (f.down == 0)
60         cout << "分母不能为0";
61     else if (f.down == 1)
62         cout << f.up;
63     else
64         cout << f.up << "/" << f.down;
65 }
66 
67 Fraction add(const Fraction& f1, const Fraction& f2) {
68     return Fraction{ f1.up * f2.down + f2.up * f1.down, f1.down * f2.down };;
69 }
70 
71 Fraction sub(const Fraction& f1, const Fraction& f2) {
72     return Fraction{ f1.up * f2.down - f2.up * f1.down, f1.down * f2.down };;
73 }
74 
75 Fraction mul(const Fraction& f1, const Fraction& f2) {
76     return Fraction{ f1.up * f2.up, f1.down * f2.down };
77 }
78 
79 Fraction div(const Fraction& f1, const Fraction& f2) {
80     return Fraction{ f1.up * f2.down, f1.down * f2.up };
81 }

task4.cpp

 1 #include "Fraction.h"
 2 #include <iostream>
 3 
 4 using std::cout;
 5 using std::endl;
 6 
 7 void test1() {
 8     cout << "Fraction类测试: " << endl;
 9     cout << Fraction::doc << endl << endl;
10 
11     Fraction f1(5);
12     Fraction f2(3, -4), f3(-18, 12);
13     Fraction f4(f3);
14 
15     cout << "f1 = "; output(f1); cout << endl;
16     cout << "f2 = "; output(f2); cout << endl;
17     cout << "f3 = "; output(f3); cout << endl;
18     cout << "f4 = "; output(f4); cout << endl;
19 
20     Fraction f5(f4.negative());
21     cout << "f5 = "; output(f5); cout << endl;
22     cout << "f5.get_up() = " << f5.get_up() << ", f5.get_down() = " <<
23         f5.get_down() << endl;
24 
25     cout << "f1 + f2 = "; output(add(f1, f2)); cout << endl;
26     cout << "f1 - f2 = "; output(sub(f1, f2)); cout << endl;
27     cout << "f1 * f2 = "; output(mul(f1, f2)); cout << endl;
28     cout << "f1 / f2 = "; output(div(f1, f2)); cout << endl;
29     cout << "f4 + f5 = "; output(add(f4, f5)); cout << endl;
30 }
31 
32 void test2() {
33     Fraction f6(42, 55), f7(0, 3);
34     cout << "f6 = "; output(f6); cout << endl;
35     cout << "f7 = "; output(f7); cout << endl;
36     cout << "f6 / f7 = "; output(div(f6, f7)); cout << endl;
37 }
38 
39 int main() {
40     cout << "测试1: Fraction类基础功能测试\n";
41     test1();
42     
43     cout << "\n测试2: 分母为0测试: \n";
44     test2();
45 }

View Code

result4

Task5

account.h

 1 #ifndef __ACCOUNT_H__
 2 #define __ACCOUNT_H__
 3 
 4 class SavingAccount {
 5 private:
 6     int id;
 7     double balance;
 8     double rate;
 9     int lastDate;
10     double accumulation;
11 
12     static double total;
13 
14     void record(int data, double amount);
15     double accumulate(int date) const {
16         return accumulation + balance * (date - lastDate);
17     }
18 
19 public:
20     SavingAccount(int date, int id, double rate);
21     int getId() const { return id; }
22     double getBalance() const { return balance; }
23     double getRate() const { return rate; }
24 
25     static double getTotal() { return total; }
26 
27     void deposit(int date, double amount);
28     void withdraw(int date, double amount);
29 
30     void settle(int date);
31 
32     void show() const;
33 };
34 
35 #endif

account.cpp

 1 #include "account.h"
 2 #include <cmath>
 3 #include <iostream>
 4 using namespace std;
 5 
 6 double SavingAccount::total = 0;
 7 
 8 SavingAccount::SavingAccount(int date, int id, double rate)
 9     : id{ id }, balance{ 0 }, rate{ rate }, lastDate{ date }, accumulation{ 0 } {
10     cout << date << "\t#" << id << "is created" << endl;
11 }
12 
13 void SavingAccount::record(int date, double amount) {
14     accumulation = accumulate(date);
15     lastDate = date;
16     amount = floor(amount * 100 + 0.5) / 100;
17     balance += amount;
18     total += amount;
19     cout << date << "\t#" << id << "\t" << amount << "\t" << balance << endl;
20 }
21 
22 void SavingAccount::deposit(int date, double amount) {
23     record(date, amount);
24 }
25 
26 void SavingAccount::withdraw(int date, double amount) {
27     if (amount > getBalance())
28         cout << "Error: not enough money" << endl;
29     else
30         record(date, -amount);
31 }
32 
33 void SavingAccount::settle(int date) {
34     double interest = accumulate(date) * rate / 365;
35     if (interest != 0)
36         record(date, interest);
37     accumulation = 0;
38 }
39 
40 void SavingAccount::show() const {
41     cout << "#" << id << "\tBalance: " << balance;
42 }

5_11.cpp

 1 #include "account.h"
 2 #include <iostream>
 3 using namespace std;
 4 
 5 int main() {
 6     SavingAccount sa0(1, 21325302, 0.015);
 7     SavingAccount sa1(1, 58320212, 0.015);
 8 
 9     sa0.deposit(5, 5000);
10     sa1.deposit(25, 10000);
11     sa0.deposit(45, 5500);
12     sa1.deposit(60, 4000);
13 
14     sa0.settle(90);
15     sa1.settle(90);
16 
17     sa0.show(); cout << endl;
18     sa1.show(); cout << endl;
19     cout << "Total: " << SavingAccount::getTotal() << endl;
20 }

result5

改进点：

利息是按天数计算的，使用了 rate / 365 来假设一年有 365 天。然而，对于利息计算，会有闰年这类特殊情况存在。

在取款函数 withdraw 中，只有在余额不足时输出错误信息，但没有抛出异常或者返回错误码。

posted on 2024-10-23 21:09 Haruto 阅读(11) 评论(0) 编辑收藏举报

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