实验任务1：
t.h源码：
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源码：
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源码：
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 }
运行测试结果截图：
问题1：
编译报错信息截图：
报错可能原因：当编译器编译这个项目时，会首先处理t.h头文件，然后处理t.cpp和task1.cpp源文件。在t.h中未对func()声明，即使在t,cpp中有func()函数，编译器并不会认为func()函数在主函数执行前便已对它进行声明。
问题2：
普通构造函数：
功能：在对象进行创建时对其初始化参数。
调用时机：创建对象时。
复制构造函数：
功能：使用一个已经存在的对象，去初始化同类的一个新对象。
调用时机：(1)用类的一个对象去初始化该类的另一个对象时；(2)函数的形参时类的对象，调用函数时，进行形参和实参结合时；(3)函数的返回值时类的对象，函数执行完成返回调用者时。
移动构造函数：
功能：将一个对象的资源移动到新的对象中，而非复制。
调用时机：利用右值引用，通过移动而不复制实参的高性能方式构建新对象。
析构函数：
功能：完成对象被删除前的一些清理工作。
调用时机：在对象的生存期即将结束的时刻被自动调用的。
问题3：
不能正确编译运行。
实验任务2：
Complex.h源码：
1 #pragma once
2
3 #include<string>
4
5 class Complex
6 {
7 public:
8 Complex(double r = 0, double i = 0);
9 Complex(const Complex& c);
10 ~Complex();
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 double abs(const Complex& c);
20 friend void output(const Complex& c);
21
22 private:
23 double real, imag;
24 public:
25 static const std::string doc;
26 };
27
28 Complex add(const Complex &c1, const Complex &c2);
29 bool is_equal(const Complex &c1, const Complex &c2);
30 bool is_not_equal(const Complex &c1, const Complex &c2);
31 double abs(const Complex &c);
32 void output(const Complex &c);
Complex.cpp源码：
1 #include <iostream>
2 #include "Complex.h"
3
4 using namespace std;
5
6 const string Complex::doc{ "a simplified complex class" };
7
8 Complex::Complex(double r, double i)
9 {
10 real = r;
11 imag = i;
12 }
13 Complex::Complex(const Complex& c)
14 {
15 real = c.real;
16 imag = c.imag;
17 }
18 Complex::~Complex() = default;
19
20 double Complex::get_real() const
21 {
22 return real;
23 }
24 double Complex::get_imag() const
25 {
26 return imag;
27 }
28 void Complex::add(const Complex& c)
29 {
30 real = real + c.real;
31 imag = imag + c.imag;
32 }
33
34 Complex add(const Complex& c1, const Complex& c2)
35 {
36 return Complex(c1.real + c2.real, c1.imag + c2.imag);
37 }
38 bool is_equal(const Complex& c1, const Complex& c2)
39 {
40 if (c1.real == c2.real && c1.imag == c2.imag)
41 return true;
42 return false;
43 }
44 bool is_not_equal(const Complex& c1, const Complex& c2)
45 {
46 if (c1.real == c2.real && c1.imag == c2.imag)
47 return false;
48 return true;
49 }
50 double abs(const Complex& c)
51 {
52 return sqrt(c.real * c.real + c.imag * c.imag);
53 }
54 void output(const Complex& c)
55 {
56 if(c.imag >= 0)
57 cout << c.real << " + " << c.imag << "i";
58 else
59 cout << c.real << " - " << -c.imag << "i";
60 }
task2.cpp源码：
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 }
运行测试结果截图：
实验任务3：
task3.cpp源码：
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 }
运行测试结果截图：
实验任务4：
Fraction.h源码：
1 #pragma once
2 #include <string>
3
4 class Fraction
5 {
6 public:
7 Fraction(int uu, int dd = 1);
8 Fraction(const Fraction& f);
9 ~Fraction();
10
11 int get_up() const;
12 int get_down() const;
13 Fraction negative();
14
15 Fraction simplify();
16
17 friend void output(const Fraction& f1);
18 friend Fraction add(const Fraction& f1, const Fraction& f2);
19 friend Fraction sub(const Fraction& f1, const Fraction& f2);
20 friend Fraction mul(const Fraction& f1, const Fraction& f2);
21 friend Fraction div(const Fraction& f1, const Fraction& f2);
22 private:
23 int up, down;
24 public:
25 static const std::string doc;
26 };
27
28 void output(const Fraction& f1);
29 Fraction add(const Fraction& f1, const Fraction& f2);
30 Fraction sub(const Fraction& f1, const Fraction& f2);
31 Fraction mul(const Fraction& f1, const Fraction& f2);
32 Fraction div(const Fraction& f1, const Fraction& f2);
Fraction.cpp源码：
1 #include "Fraction.h"
2 #include <iostream>
3
4 using namespace std;
5
6 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" };
7
8 Fraction::Fraction(int uu, int dd)
9 {
10 up = uu;
11 down = dd;
12 }
13 Fraction::Fraction(const Fraction& f)
14 {
15 up = f.up;
16 down = f.down;
17 }
18 Fraction::~Fraction() = default;
19
20 int Fraction::get_up() const
21 {
22 return up;
23 }
24 int Fraction::get_down() const
25 {
26 return down;
27 }
28 Fraction Fraction::negative()
29 {
30 Fraction temp = simplify();
31 return Fraction(-temp.up, temp.down);
32 }
33
34 Fraction Fraction::simplify()
35 {
36 int small, uu, dd, pos_or_neg;
37 if (up >= 0)
38 {
39 uu = up;
40 if (down > 0)
41 {
42 dd = down;
43 pos_or_neg = 1;
44 }
45 else
46 {
47 dd = -down;
48 pos_or_neg = -1;
49 }
50 }
51 else
52 {
53 uu = -up;
54 if (down > 0)
55 {
56 dd = down;
57 pos_or_neg = -1;
58 }
59 else
60 {
61 dd = -down;
62 pos_or_neg = 1;
63 }
64 }
65 if (uu > dd)
66 small = dd;
67 else
68 small = uu;
69 for (int i = small; i >= 1; i--)
70 if (uu % i == 0 && dd % i == 0)
71 {
72 uu = uu / i;
73 dd = dd / i;
74 break;
75 }
76 if (pos_or_neg == 1)
77 return Fraction(uu, dd);
78 return Fraction(-uu, dd);
79 }
80
81 void output(const Fraction& f)
82 {
83 Fraction temp = Fraction(f.up, f.down);
84 temp = temp.simplify();
85 if (temp.down == 0)
86 cout << "分母不能为0";
87 else
88 {
89 if (temp.up == 0)
90 cout << "0";
91 else if (temp.up != 0 && temp.down == 1)
92 cout << temp.up;
93 else
94 cout << temp.up << "/" << temp.down;
95 }
96 }
97
98 Fraction add(const Fraction& f1, const Fraction& f2)
99 {
100 return Fraction(f1.up * f2.down + f2.up * f1.down, f1.down * f2.down);
101 }
102 Fraction sub(const Fraction& f1, const Fraction& f2)
103 {
104 return Fraction(f1.up * f2.down - f2.up * f1.down, f1.down * f2.down);
105 }
106 Fraction mul(const Fraction& f1, const Fraction& f2)
107 {
108 return Fraction(f1.up * f2.up, f1.down * f2.down);
109 }
110 Fraction div(const Fraction& f1, const Fraction& f2)
111 {
112 return Fraction(f1.up * f2.down, f1.down * f2.up);
113 }
task4.cpp源码：
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 }
运行测试结果截图：
实验任务5：
account.h源码：
1 #pragma once
2 #ifndef ACCOUNT_H
3 #define ACCOUNT_H
4 class SavingsAccount {
5 private:
6 int id; //账号
7 double balance; //余额
8 double rate; //存款的年利率
9 int lastDate; //上次变更余额的时期
10 double accumulation; //余额按日累加之和
11 static double total; //所有账户的总金额
12 //记录一笔账，date为日期，amount为金额，desc为说明
13 void record(int date, double amount);
14 //获得到指定日期为止的存款金额按日累积值
15 double accumulate(int date) const {
16 return accumulation + balance * (date - lastDate);
17 }
18 public:
19 //构造函数
20 SavingsAccount(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 static double getTotal() { return total; }
25 void deposit(int date, double amount); //存入现金
26 void withdraw(int date, double amount); //取出现金
27 //利息结算，每年1月1日调用一次该函数
28 void settle(int date);
29 //显示账户信息
30 void show() const;
31 };
32 #endif //__ACCOUNT_H__
account.cpp源码：
1 #include"account.h"
2 #include<cmath>
3 #include<iostream>
4 using namespace std;
5
6 double SavingsAccount::total = 0;
7 //SavingsAccount类相关成员函数的实现
8 SavingsAccount::SavingsAccount(int date, int id, double rate) :id(id), balance(0), rate(rate), lastDate(date), accumulation(0) {
9 cout << date << "\t#" << id << "is created" << endl;
10 }
11 void SavingsAccount::record(int date, double amount) {
12 accumulation = accumulate(date);
13 lastDate = date;
14 amount = floor(amount * 100 + 0.5) / 100; //保留小数点后两位
15 balance += amount;
16 total += amount;
17 cout << date << "\t#" << id << "\t" << amount << "\t" << balance << endl;
18 }
19 void SavingsAccount::deposit(int date, double amount) {
20 record(date, amount);
21 }
22 void SavingsAccount::withdraw(int date, double amount) {
23 if (amount > getBalance())
24 cout << "Error：not enough money" << endl;
25 else
26 record(date, -amount);
27 }
28 void SavingsAccount::settle(int date) {
29 double interest = accumulate(date) * rate / 365; //计算年息
30 if (interest != 0)
31 record(date, interest);
32 accumulation = 0;
33 }
34 void SavingsAccount::show() const {
35 cout << "#" << id << "\tBalance：" << balance;
36 }
5_11.cpp源码：
1 #include"account.h"
2 #include<iostream>
3 using namespace std;
4 int main() {
5 //建立几个账户
6 SavingsAccount sa0(1, 21325302, 0.015);
7 SavingsAccount sa1(1, 58320212, 0.015);
8 //几笔账目
9 sa0.deposit(5, 5000);
10 sa1.deposit(25, 10000);
11 sa0.deposit(45, 5500);
12 sa1.withdraw(60, 4000);
13 //开户后第90天到了银行的计息日，结算所有账户的年息
14 sa0.settle(90);
15 sa1.settle(90);
16 //输出各个账户信息
17 sa0.show(); cout << endl;
18 sa1.show(); cout << endl;
19 cout << "Total：" << SavingsAccount::getTotal() << endl;
20 return 0;
21 }
运行测试结果截图：
分析：增加const关键字提高数据的安全性。使用静态数据成员total记录总金额，提高了使用性。
总结：
1.多文件结构的使用需要注意不同文件中操作的对象，如果对类的实现的文件修改，要注意是否在类的定义文件中同步。
2.const int返回类型 与 const成员函数 是两个不同的原型。
3.注意函数间相互调用，因为返回值类型不同导致的错误。
标签：const,对象,double,编程,int,Complex,实验,Fraction,include From： https://www.cnblogs.com/wuxin404/p/18496345