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 }
View Code
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。