task 1
代码：
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();
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 }
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 }
运行结果截图：
回答问题：
问题1：
答：func()函数需要在类外声明，不然就会显示func()函数没有定义。
问题2：
答：
普通构造函数T(int x = 0, int y = 0)，传入两个参数x，y来创建一个实例，并且x,y在默认情况下都是0。
复制构造函数T(const T& t)，传入参数是一个已经存在的对象，会复制这个已有对象的x,y来创建一个新的对象。
移动构造函数T(T &&t)，右值引用，将已经存在对象的x,y移动过来创建一个新的对象，并且原对象不再拥有原来的x,y。
构造函数在每次对象的创建时会调用，根据不同答参数传入和预期功能，分别调用合适的构造函数，特别的，复制构造函数在对象作为函数参数传递时也会调用。析构函数在每个对象生命周期结束时会被调用。
问题3：
答：不能正确编译运行
task2
代码：
Complex.h
1 #pragma once
2 #include <string>
3
4 using std::string;
5
6 class Complex {
7 public:
8 Complex();
9 Complex(double r, double i = 0);
10 Complex(const Complex& c);
11
12 double get_real() const;
13 double get_imag() const;
14 void add(const Complex& c);
15
16 friend Complex add(const Complex& c1, const Complex& c2);
17 friend bool is_equal(const Complex& c1, const Complex& c2);
18 friend bool is_not_equal(const Complex& c1, const Complex& c2);
19 friend void output(const Complex& c);
20 friend double abs(const Complex& c);
21
22 private:
23 double real, imag;
24
25 public:
26 static const string doc;
27 };
Complex.cpp
1 #include <iostream>
2 #include "Complex.h"
3
4 using std::string;
5 using std::cout;
6 using std::endl;
7
8 const string Complex::doc{ "a simplified complex class" };
9
10 Complex::Complex():real{0}, imag{0}{}
11 Complex::Complex(double r, double i): real{r}, imag{i}{}
12 Complex::Complex(const Complex& c):real{c.real}, imag{c.imag}{}
13
14 double Complex::get_real() const { return real; }
15 double Complex::get_imag() const { return imag; }
16 void Complex::add(const Complex& c) {
17 real += c.real;
18 imag += c.imag;
19 }
20
21 Complex add(const Complex& c1, const Complex& c2) {
22 Complex c3;
23 c3.real = c1.real + c2.real;
24 c3.imag = c1.imag + c2.imag;
25 return c3;
26 }
27
28 bool is_equal(const Complex& c1, const Complex& c2) {
29 if (c1.real == c2.real && c1.imag == c2.imag)
30 return true;
31 else
32 return false;
33 }
34
35 bool is_not_equal(const Complex& c1, const Complex& c2) {
36 if (c1.real == c2.real && c1.imag == c2.real)
37 return false;
38 else
39 return true;
40 }
41
42 void output(const Complex& c) {
43 cout << c.real;
44 if (c.imag >= 0)
45 cout << " + " << c.imag << "i" << endl;
46 else
47 cout << " - " << abs(c.imag) << "i" << endl;
48
49
50 }
51
52 double abs(const Complex& c) {
53 return sqrt(c.real * c.real + c.imag * c.imag);
54 }
task2.cpp
1 #include "Complex.h"
2 #include <iostream>
3
4 using std::cout;
5 using std::endl;
6 using std::boolalpha;
7
8 void test() {
9 cout << "类成员测试: " << endl;
10 cout << Complex::doc << endl;
11
12 cout << endl;
13
14 cout << "Complex对象测试: " << endl;
15 Complex c1;
16 Complex c2(3, -4);
17 const Complex c3(3.5);
18 Complex c4(c3);
19
20 cout << "c1 = "; output(c1); cout << endl;
21 cout << "c2 = "; output(c2); cout << endl;
22 cout << "c3 = "; output(c3); cout << endl;
23 cout << "c4 = "; output(c4); cout << endl;
24 cout << "c4.real = " << c4.get_real() << ", c4.imag = " << c4.get_imag() << endl;
25
26 cout << endl;
27
28 cout << "复数运算测试: " << endl;
29 cout << "abs(c2) = " << abs(c2) << endl;
30 c1.add(c2);
31 cout << "c1 += c2, c1 = "; output(c1); cout << endl;
32 cout << boolalpha;
33 cout << "c1 == c2 : " << is_equal(c1, c2) << endl;
34 cout << "c1 != c3 : " << is_not_equal(c1, c3) << endl;
35 c4 = add(c2, c3);
36 cout << "c4 = c2 + c3, c4 = "; output(c4); cout << endl;
37 }
38
39 int main() {
40 test();
41 }
运行结果截图：
task3
代码：
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() << endl;
21 cout << endl;
22
23 cout << "复数运算测试: " << endl;
24 cout << "abs(c2) = " << abs(c2) << endl;
25 c1 += c2;
26 cout << "c1 += c2, c1 = " << c1 << endl;
27 cout << boolalpha;
28 cout << "c1 == c2 : " << (c1 == c2) << endl;
29 cout << "c1 != c3 : " << (c1 != c3) << endl;
30 c4 = c2 + c3;
31 cout << "c4 = c2 + c3, c4 = " << c4 << endl;
32 }
33
34 int main() {
35 test();
36 }
测试结果截图：
回答问题：
问题1：
答：在输出复数时能直接cout，而不用调用output()函数；在进行+=、+等运算时，能够像普通数字运算那样直接进行；在判断是否相等时，也能够用==、!=来判断。
问题2：
答：标准库complex模板类大大方便了使用复数时的操作。不过同样的功能，我们也可以在自定义类里通过操作函数来实现。
task4
代码：
Fraction.h
1 #pragma
2 #include<string>
3
4 using namespace std;
5
6 class Fraction {
7 public:
8 Fraction(int u, int d = 1);
9 Fraction(const Fraction & f);
10
11 int get_up() const;
12 int get_down() const;
13 Fraction negative() const;
14
15 private:
16 int up, down;
17
18 public:
19 static const string doc;
20
21 friend void output(const Fraction f);
22 friend Fraction add(const Fraction f1, const Fraction f2);
23 friend Fraction sub(const Fraction f1, const Fraction f2);
24 friend Fraction mul(const Fraction f1, const Fraction f2);
25 friend Fraction div(const Fraction f1, const Fraction f2);
26
27 };
28
29 void output(const Fraction f);
30 Fraction add(const Fraction f1, const Fraction f2);
31 Fraction sub(const Fraction f1, const Fraction f2);
32 Fraction mul(const Fraction f1, const Fraction f2);
33 Fraction div(const Fraction f1, const Fraction f2);
Fraction.cpp
1 #include<iostream>
2 #include<string>
3 #include"Fraction.h"
4
5 using namespace std;
6
7 const 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" };
8
9 Fraction::Fraction(int u, int d) {
10 int i = 1;
11 if (u < 0)
12 i = -i;
13 if (d < 0)
14 i = -i;
15
16 int p = abs(u);
17 int q = abs(d);
18 if (u != 0 && d != 0) {
19 int a = max(p, q);
20 int b = min(p, q);
21 int r = a % b;
22 while (r != 0) {
23 a = b;
24 b = r;
25 r = a % b;
26 }
27
28 up = i * p / b;
29 down = q / b;
30
31 }
32 else {
33 up = u;
34 down = d;
35 }
36 }
37 Fraction::Fraction(const Fraction & f) : up{ f.up }, down{ f.down } {}
38
39 int Fraction::get_up() const {
40 return up;
41 }
42 int Fraction::get_down() const {
43 return down;
44 }
45 Fraction Fraction::negative() const {
46 Fraction f(1);
47 f.up = -up;
48 f.down = down;
49 return f;
50 }
51
52 //最大公因数
53 int func(int x, int y) {
54 if (x == 0 || y == 0)
55 return 1;
56 int a = max(x, y);
57 int b = min(x, y);
58 int r = a % b;
59 while(r != 0){
60 a = b;
61 b = r;
62 r = a % b;
63 }
64
65 return b;
66 }
67
68 void output(Fraction f) {
69 int t = func(abs(f.up), abs(f.down));
70 int up = abs(f.up) / t;
71 int down = abs(f.down) / t;
72
73 if (f.down == 0)
74 cout << "分母不能为0" << endl;
75 else if (f.up == 0)
76 cout << "0" << endl;
77 else if (f.down == 1)
78 cout << f.up << endl;
79 else {
80 if ((f.up < 0 && f.down > 0) || (f.up > 0 && f.down < 0))
81 cout << "-";
82 cout << up << "/" << down << endl;
83 }
84
85 }
86
87 Fraction add(const Fraction f1, const Fraction f2) {
88 Fraction f(1);
89 f.down = f1.down * f2.down / func(f1.down, f2.down);
90 f.up = f1.up * f.down / f1.down + f2.up * f.down / f2.down;
91 return f;
92 }
93
94 Fraction sub(const Fraction f1, const Fraction f2) {
95 Fraction f(1);
96 f.down = f1.down * f2.down / func(f1.down, f2.down);
97 f.up = f1.up * f.down / f1.down - f2.up * f.down / f2.down;
98 return f;
99 }
100
101 Fraction mul(const Fraction f1, const Fraction f2) {
102 Fraction f(1);
103 f.up = f1.up * f2.up;
104 f.down = f1.down * f2.down;
105 return f;
106 }
107
108 Fraction div(const Fraction f1, const Fraction f2) {
109 Fraction f(1);
110 if (f2.up == 0 || f2.down == 0)
111 f.up = f.down = 0;
112 else {
113 f.up = f1.up * f2.down;
114 f.down = f1.down * f2.up;
115 }
116 return f;
117 }
task4.cpp
1 #include "Fraction.h"
2 #include <iostream>
3
4 using std::cout;
5 using std::endl;
6
7
8 void test1() {
9 cout << "Fraction类测试: " << endl;
10 cout << Fraction::doc << endl << endl;
11
12 Fraction f1(5);
13 Fraction f2(3, -4), f3(-18, 12);
14 Fraction f4(f3);
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() = " << f5.get_down() << endl;
23
24 cout << "f1 + f2 = "; output(add(f1, f2)); cout << endl;
25 cout << "f1 - f2 = "; output(sub(f1, f2)); cout << endl;
26 cout << "f1 * f2 = "; output(mul(f1, f2)); cout << endl;
27 cout << "f1 / f2 = "; output(div(f1, f2)); cout << endl;
28 cout << "f4 + f5 = "; output(add(f4, f5)); cout << endl;
29 }
30
31 void test2() {
32 Fraction f6(42, 55), f7(0, 3);
33 cout << "f6 = "; output(f6); cout << endl;
34 cout << "f7 = "; output(f7); cout << endl;
35 cout << "f6 / f7 = "; output(div(f6, f7)); cout << endl;
36 }
37
38 int main() {
39 cout << "测试1: Fraction类基础功能测试\n";
40 test1();
41
42 cout << "\n测试2: 分母为0测试: \n";
43 test2();
44 }
运行结果截图：
task5
代码：
account.h
1 #pragma once
2
3 class SavingAccount {
4 private:
5 int id;
6 double balance;
7 double rate;
8 int lastDate;
9 double accumulation;
10
11 static double total;
12
13 void record(int date, double amount);
14
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
22 int getId() const { return id; }
23 double getBalance() const { return balance; }
24 double getRate() const { return rate; }
25
26 static double getTotal() { return total; }
27
28 void deposit(int date, double amount);
29 void withdraw(int date, double amount);
30 void settle(int date);
31 void show() const;
32
33 };
account.cpp
1 #include"account.h"
2 #include<iostream>
3 #include<cmath>
4
5 using namespace std;
6
7 double SavingAccount::total = 0;
8
9 SavingAccount::SavingAccount(int date, int id, double rate)
10 : id(id), balance(0), rate(rate), lastDate(date), accumulation(0) {
11 cout << date << "\t#" << id << "is created" << endl;
12 }
13
14 void SavingAccount::record(int date, double amount) {
15 accumulation = accumulate(date);
16 lastDate = date;
17 amount = floor(amount * 100 + 0.5) / 100;
18 balance += amount;
19 total += amount;
20 cout << date << "\t#" << id << "\t" << amount << "\t" << balance << endl;
21 }
22
23 void SavingAccount::deposit(int date, double amount) {
24 record(date, amount);
25 }
26
27 void SavingAccount::withdraw(int date, double amount) {
28 if (amount > getBalance())
29 cout << "Error: not enough money" << endl;
30 else
31 record(date, -amount);
32 }
33
34 void SavingAccount::settle(int date) {
35 double interest = accumulate(date) * rate / 365;
36 if (interest != 0)
37 record(date, interest);
38 accumulation = 0;
39 }
40
41 void SavingAccount::show() const {
42 cout << "#" << id << "\tBalance: " << balance;
43 }
5_11.cpp
1 #include "account.h"
2 #include <iostream>
3
4 using namespace std;
5
6 int main() {
7 SavingAccount sa0(1, 21325302, 0.015);
8 SavingAccount sa1(1, 58320212, 0.015);
9
10 sa0.deposit(5, 5000);
11 sa1.deposit(25, 10000);
12 sa0.deposit(45, 5500);
13 sa1.withdraw(60, 4000);
14
15 sa0.settle(90);
16 sa1.settle(90);
17
18 sa0.show(); cout << endl;
19 sa1.show(); cout << endl;
20 cout << "Total: " << SavingAccount::getTotal() << endl;
21
22 }
运行结果截图：
回答问题：
合理，有疑问：计算完年息之后accumulation为什么要重置为0？
标签：const,对象,double,编程,int,Complex,实验,Fraction,include From： https://www.cnblogs.com/forgiver/p/18494358