任务1
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
运行截图
问题1：
去掉line36，不能正确运行，报错信息为：
可能的原因为：func只在类T中声明为友元函数，未声明为普通函数
问题2：
普通构造函数：构造函数用于初始化对象的成员变量，分配资源或执行任何启动操作。
复制构造函数：用于通过已有对象创建新对象，通常采用传值方式。
移动构造函数：用于高效地转移资源，通常在对象的资源很重的情况下使用，避免不必要的拷贝。
构造函数在创建对象时自动调用；析构函数在对象的生命周期结束时自动调用。
问题3：
不能正确编译运行，报错信息为：
任务2
Complex.h
1 #pragma once
2 #include <iostream>
3 #include <cmath>
4
5 class Complex {
6 public:
7 Complex(); // 默认构造函数
8 Complex(double real, double imag); // 构造函数
9 Complex(double real) ; // 单参构造函数
10 Complex(const Complex& other); // 拷贝构造函数
11
12 double get_real() const; // 返回实部
13 double get_imag() const; // 返回虚部
14 Complex add(const Complex& c);
15 friend Complex add(const Complex& c1, const Complex& c2) ; // 复数相加
16 friend bool is_equal(const Complex& c1, const Complex& c2) ; // 判断相等
17 friend bool is_not_equal(const Complex& c1, const Complex& c2) ; // 判断不相等
18 friend double abs(Complex &c) ; // 取模
19 friend void output(const Complex &c) ; // 输出复数
20
21 static std::string doc ;
22 private:
23 double real; // 实部
24 double imag; // 虚部
25 };
View Code
Complex.cpp
1 #include "Complex.h"
2 #include<iostream>
3
4 // 默认构造函数
5 Complex::Complex() : real(0), imag(0) {}
6
7
8 // 构造函数
9 Complex::Complex(double real, double imag) : real(real), imag(imag) {}
10
11 //单参构造函数
12 Complex::Complex(double real): real(real), imag(0) {}
13
14 // 拷贝构造函数
15 Complex::Complex(const Complex& other) : real(other.real), imag(other.imag) {}
16
17 // 返回实部
18 double Complex::get_real() const {
19 return real;
20 }
21
22 // 返回虚部
23 double Complex::get_imag() const {
24 return imag;
25 }
26
27 Complex Complex::add(const Complex& c) {
28 return Complex(real + c.real, imag + c.imag);
29 }
30
31 // 复数相加
32 Complex add(const Complex& c1, const Complex& c2) {
33 return Complex(c1.real + c2.real, c1.imag + c2.imag);
34 }
35
36 // 判断相等
37 bool is_equal(const Complex& c1, const Complex& c2) {
38 return (c1.real == c2.real && c1.imag == c2.imag);
39 }
40
41 // 判断不相等
42 bool is_not_equal(const Complex & c1, const Complex & c2) {
43 return !is_equal(c1,c2);
44 }
45
46 // 取模
47 double abs(Complex &c) {
48 return sqrt(c.real * c.real + c.imag * c.imag);
49 }
50
51 // 输出复数
52 void output(const Complex &c) {
53 std::cout << c.real << (c.imag >= 0 ? "+" : "") << c.imag << "i";
54 }
55
56 std::string Complex::doc="A simplified class" ;
View Code
Main.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 }
View Code
运行截图：
任务3
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() << 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 }
View Code
运行结果：
接口有默认构造函数，普通构造函数，单参构造函数，复制构造函数，real,imag,abs,复数加法，判断复数是否相等
对比任务2：
1.c1 += c2代替c1.add(c2)，(c1 == c2)代替is_equal(c1, c2)，(c1 != c3)代替is_not_equal(c1, c3)，对象名能直接输出
2：可以用运算符重载来简化类的操作
任务4
Fraction.h
1 #pragma once
2 #include <iostream>
3 #include <numeric>
4
5 class Fraction {
6 private:
7 int up; // 分子
8 int down; // 分母
9
10 void simplify(); // 简化分数
11
12 public:
13 static const std::string doc; // 描述信息
14
15 Fraction(int numerator = 0, int denominator = 1); // 构造函数
16 Fraction(const Fraction &f); // 拷贝构造函数
17
18 int get_up() const; // 返回分子
19 int get_down() const; // 返回分母
20 Fraction negative() const; // 求负
21
22 friend void output(const Fraction &f); //输出
23 friend Fraction add(const Fraction &f1, const Fraction &f2);
24 friend Fraction sub(const Fraction &f1, const Fraction &f2);
25 friend Fraction mul(const Fraction &f1, const Fraction &f2);
26 friend Fraction div(const Fraction &f1, const Fraction &f2);
27
28
29 };
30
31 int gcd1(int a,int b);
View Code
Fraction.cpp
1 #include "Fraction.h"
2 #include<iostream>
3
4 const std::string Fraction::doc = "Fraction类 v 0.01版. 目前仅支持分数对象的构造、输出、加/减/乘/除运算。";
5
6
7 int gcd1(int a,int b)
8 {
9 return b==0?a:gcd1(b,a%b);
10 }
11
12 Fraction::Fraction(int numerator, int denominator) : up(numerator), down(denominator) {
13 if (down == 0) {
14 std::cout<<"分母不能为0"<<std::endl;
15 }
16 simplify();
17 }
18
19 Fraction::Fraction(const Fraction &f) : up(f.up), down(f.down) {}
20
21 void Fraction::simplify() {
22 int gcd = gcd1(up, down);
23 up /= gcd;
24 down /= gcd;
25 if (down < 0) { // 保持负号在分子上
26 up = -up;
27 down = -down;
28 }
29 }
30
31 int Fraction::get_up() const {
32 return up;
33 }
34
35 int Fraction::get_down() const {
36 return down;
37 }
38
39 Fraction Fraction::negative() const {
40 return Fraction(-up, down);
41 }
42
43 void output(const Fraction &f){
44 if(f.down!=0){
45
46 if(f.down==1)
47 std::cout<<f.up<<std::endl;
48 else
49 std::cout<<f.up<<"/"<<f.down<<std::endl;
50 }
51 }
52
53 Fraction add(const Fraction &f1, const Fraction &f2) {
54 return Fraction(f1.up * f2.down + f2.up * f1.down, f1.down * f2.down);
55 }
56
57 Fraction sub(const Fraction &f1, const Fraction &f2) {
58 return Fraction(f1.up * f2.down - f2.up * f1.down, f1.down * f2.down);
59 }
60
61 Fraction mul(const Fraction &f1, const Fraction &f2) {
62 return Fraction(f1.up * f2.up, f1.down * f2.down);
63 }
64
65 Fraction div(const Fraction &f1, const Fraction &f2) {
66 if (f2.up == 0) {
67 std::cout<<"分母不能为0"<<std::endl;
68 }
69 else
70 return Fraction(f1.up * f2.down, f1.down * f2.up);
71 }
72
View Code
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 }
View Code
运行截图：
任务5
account.h
1 #pragma once
2 class SavingsAccount {
3 private:
4 int id;
5 double balance;
6 double rate;
7 int lastDate;
8 double accumulation;
9 static double total;
10 void record(int date,double amount);
11 double accumulate(int date) const {
12 return accumulation+balance*(date-lastDate);
13 }
14 public:
15 SavingsAccount(int date,int id,double rate);
16 int getId() const {return id;}
17 double getBalance() const {return balance;}
18 double getRate() const {return rate;}
19 static double getTotal() {return total;}
20 void deposit(int date,double amount);
21 void withdraw(int date,double amount);
22 void settle(int date);
23 void show() const;
24 };
View Code
account.cpp
1 #include "account.h"
2 #include <cmath>
3 #include <iostream>
4 using namespace std;
5
6 double SavingsAccount::total=0;
7 SavingsAccount::SavingsAccount(int date,int id,double rate):id(id),balance(0),rate(rate),lastDate(date),accumulation(0){
8 cout<<date<<"\t#"<<id<<" is created"<<endl;
9 }
10 void SavingsAccount::record(int date,double amount) {
11 accumulation=accumulate(date);
12 lastDate=date;
13 amount=floor(amount*100+0.5)/100;
14 balance+=amount;
15 total+=amount;
16 cout<<date<<"\t#"<<id<<"\t"<<amount<<"\t"<<balance<<endl;
17 }
18
19 void SavingsAccount::deposit(int date,double amount) {
20 record(date,amount);
21 }
22
23
24 void SavingsAccount::withdraw(int date,double amount) {
25 if(amount>getBalance())
26 cout<<"Error:not enough money"<<endl;
27 else
28 record(date,-amount);
29 }
30 void SavingsAccount::settle(int date) {
31 double interest=accumulate(date)*rate/365;
32 if(interest!=0)
33 record(date,interest);
34 accumulation=0;
35 }
36 void SavingsAccount::show() const {
37 cout<<"#"<<id<<"\tBalance:"<<balance;
38 }
39
40
View Code
5_11.cpp
1 #include "account.h"
2 #include <iostream>
3 using namespace std;
4 int main()
5 {
6 SavingsAccount sa0(1,21325302,0.015);
7 SavingsAccount sa1(1,58320212,0.015);
8
9 sa0.deposit(5,5000);
10 sa1.deposit(25,10000);
11 sa0.deposit(45,5500);
12 sa1.withdraw(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:"<<SavingsAccount::getTotal()<<endl;
20 return 0;
21 }
View Code
改进建议：
可以将四舍五入金额的逻辑封装到一个单独的工具函数中，以促进代码的重用。
考虑使用更具描述性的输出格式。例如，使用一致的格式化输出消息可以提高清晰度。
添加一个专门用于检索当前余额的方法，无需调用 show 方法。
尽可能为不改变类状态的方法添加 const 修饰符。这包括没有产生副作用的 accumulate() 和 getBalance() 方法。
如果您引入常量（如每日利息计算），考虑将它们定义为类常量。
标签：const,对象,double,int,Complex,实验,Fraction,构造函数 From： https://www.cnblogs.com/sjc666/p/18494460