任务1：
源码：
1 #pragma once
2
3 #include <iostream>
4 #include <string>
5
6 using std::string;
7 using std::cout;
8
9 // 按钮类
10 class Button {
11 public:
12 Button(const string &text);
13 string get_label() const;
14 void click();
15
16 private:
17 string label;
18 };
19
20 Button::Button(const string &text): label{text} {
21 }
22
23 inline string Button::get_label() const {
24 return label;
25 }
26
27 void Button::click() {
28 cout << "Button '" << label << "' clicked\n";
29 }
1 #pragma once
2 #include "button.hpp"
3 #include <vector>
4 #include <iostream>
5
6 using std::vector;
7 using std::cout;
8 using std::endl;
9
10 // 窗口类
11 class Window{
12 public:
13 Window(const string &win_title);
14 void display() const;
15 void close();
16 void add_button(const string &label);
17
18 private:
19 string title;
20 vector<Button> buttons;
21 };
22
23 Window::Window(const string &win_title): title{win_title} {
24 buttons.push_back(Button("close"));
25 }
26
27 inline void Window::display() const {
28 string s(40, '*');
29
30 cout << s << endl;
31 cout << "window title: " << title << endl;
32 cout << "It has " << buttons.size() << " buttons: " << endl;
33 for(const auto &i: buttons)
34 cout << i.get_label() << " button" << endl;
35 cout << s << endl;
36 }
37
38 void Window::close() {
39 cout << "close window '" << title << "'" << endl;
40 buttons.at(0).click();
41 }
42
43 void Window::add_button(const string &label) {
44 buttons.push_back(Button(label));
45 }
1 #include "window.hpp"
2 #include <iostream>
3
4 using std::cout;
5 using std::cin;
6
7 void test() {
8 Window w1("new window");
9 w1.add_button("maximize");
10 w1.display();
11 w1.close();
12 }
13
14 int main() {
15 cout << "用组合类模拟简单GUI:\n";
16 test();
17 }
结果：
回答：
问题1：这个模拟简单GUI的示例代码中，自定义了几个类？使用到了标准库的哪几个类？， 哪些类和类之间存在组合关系？ 两个类， vector， button类是vector中的元素，该vector是window类的成员。 问题2：在自定义类Button和Window中，有些成员函数定义时加了const, 有些设置成了 inline。如果你是类的设计者，目前那些没有加const或没有设置成inline的，适合添加const， 适合设置成inline吗？你的思考依据是？ Button::click和Window::close不适合加inline,在实际项目中该函数运行的内容较复杂，不必添加const，因为没有数据的传输。 Window::add不适合加inline，需要更改对象内容。 问题3：类Window的定义中，有这样一行代码，其功能是？ 窗口分隔线。任务2：
源码：
1 #include <iostream>
2 #include <vector>
3
4 using namespace std;
5
6 void output1(const vector<int> &v) {
7 for(auto &i: v)
8 cout << i << ", ";
9 cout << "\b\b \n";
10 }
11
12 void output2(const vector<vector<int>> v) {
13 for(auto &i: v) {
14 for(auto &j: i)
15 cout << j << ", ";
16 cout << "\b\b \n";
17 }
18 }
19
20 void test1() {
21 vector<int> v1(5, 42);
22 const vector<int> v2(v1);
23
24 v1.at(0) = -999;
25 cout << "v1: "; output1(v1);
26 cout << "v2: "; output1(v2);
27 cout << "v1.at(0) = " << v1.at(0) << endl;
28 cout << "v2.at(0) = " << v2.at(0) << endl;
29 }
30
31 void test2() {
32 vector<vector<int>> v1{{1, 2, 3}, {4, 5, 6, 7}};
33 const vector<vector<int>> v2(v1);
34
35 v1.at(0).push_back(-999);
36 cout << "v1: \n"; output2(v1);
37 cout << "v2: \n"; output2(v2);
38
39 vector<int> t1 = v1.at(0);
40 cout << t1.at(t1.size()-1) << endl;
41
42 const vector<int> t2 = v2.at(0);
43 cout << t2.at(t2.size()-1) << endl;
44 }
45
46 int main() {
47 cout << " 1:\n";
48 test1();
49
50 cout << "\n 2:\n";
51 test2();
52 }
结果：
答：
问题1：测试1模块中，这三行代码的功能分别是？ 构造大小为5，元素值为42的vector对象。 利用v1复制构造v2。 将v1的第一个值改为-999. 问题2：测试2模块中，这三行代码的功能分别是？ 构造以vector对象为元素的vector对象。 利用v1复制构造v2。 获取v1中的第一个vector对象元素，并在该对象末尾增加元素-999。 问题3：测试2模块中，这四行代码的功能分别是？ 将v1中第一个元素值付给t1的第一个元素。 输出t1的最后一个元素值。 将v2中第一个元素值付给t2的第一个元素。 输出t2的最后一个元素值。 问题4：根据执行结果，反向分析、推断： ① 标准库模板类vector内部封装的复制构造函数，其实现机制是深复制还是浅复制？ 深复制 ② 模板类vector的接口at(), 是否至少需要提供一个const成员函数作为接口？ 是任务3：
源码：
1 #pragma once
2
3 #include <iostream>
4 #include <cassert>
5
6 using std::cout;
7 using std::endl;
8
9 // 动态int数组对象类
10 class vectorInt{
11 public:
12 vectorInt(int n);
13 vectorInt(int n, int value);
14 vectorInt(const vectorInt &vi);
15 ~vectorInt();
16
17 int& at(int index);
18 const int& at(int index) const;
19
20 vectorInt& assign(const vectorInt &v);
21 int get_size() const;
22
23 private:
24 int size;
25 int *ptr; // ptr指向包含size个int的数组
26 };
27
28 vectorInt::vectorInt(int n): size{n}, ptr{new int[size]} {
29 }
30
31 vectorInt::vectorInt(int n, int value): size{n}, ptr{new int[size]} {
32 for(auto i = 0; i < size; ++i)
33 ptr[i] = value;
34 }
35
36 vectorInt::vectorInt(const vectorInt &vi): size{vi.size}, ptr{new int[size]} {
37 for(auto i = 0; i < size; ++i)
38 ptr[i] = vi.ptr[i];
39 }
40
41 vectorInt::~vectorInt() {
42 delete [] ptr;
43 }
44
45 const int& vectorInt::at(int index) const {
46 assert(index >= 0 && index < size);
47
48 return ptr[index];
49 }
50
51 int& vectorInt::at(int index) {
52 assert(index >= 0 && index < size);
53
54 return ptr[index];
55 }
56
57 vectorInt& vectorInt::assign(const vectorInt &v) {
58 delete[] ptr; // 释放对象中ptr原来指向的资源
59
60 size = v.size;
61 ptr = new int[size];
62
63 for(int i = 0; i < size; ++i)
64 ptr[i] = v.ptr[i];
65
66 return *this;
67 }
68
69 int vectorInt::get_size() const {
70 return size;
71 }
1 #include "vectorInt.hpp"
2 #include <iostream>
3
4 using std::cin;
5 using std::cout;
6
7 void output(const vectorInt &vi) {
8 for(auto i = 0; i < vi.get_size(); ++i)
9 cout << vi.at(i) << ", ";
10 cout << "\b\b \n";
11 }
12
13
14 void test1() {
15 int n;
16 cout << "Enter n: ";
17 cin >> n;
18
19 vectorInt x1(n);
20 for(auto i = 0; i < n; ++i)
21 x1.at(i) = i*i;
22 cout << "x1: "; output(x1);
23
24 vectorInt x2(n, 42);
25 vectorInt x3(x2);
26 x2.at(0) = -999;
27 cout << "x2: "; output(x2);
28 cout << "x3: "; output(x3);
29 }
30
31 void test2() {
32 const vectorInt x(5, 42);
33 vectorInt y(10, 0);
34
35 cout << "y: "; output(y);
36 y.assign(x);
37 cout << "y: "; output(y);
38
39 cout << "x.at(0) = " << x.at(0) << endl;
40 cout << "y.at(0) = " << y.at(0) << endl;
41 }
42
43 int main() {
44 cout << "测试1: \n";
45 test1();
46
47 cout << "\n测试2: \n";
48 test2();
49 }
结果：
答：
问题1：vectorInt类中，复制构造函数（line14)的实现，是深复制还是浅复制？ 深复制 问题2：vectorInt类中，这两个at()接口，如果返回值类型改成int而非int&（相应地，实现部 分也同步修改），测试代码还能正确运行吗？ 能 如果把line18返回值类型前面的const掉，针对 这个测试代码，是否有潜在安全隐患？尝试分析说明。 有，内部元素值会被修改。 问题3：vectorInt类中，assign()接口，返回值类型可以改成vectorInt吗？你的结论，及，原 因分析。 不能，增加了拷贝开销。任务4：
源码：
1 #pragma once
2
3 #include <iostream>
4 #include <cassert>
5
6 using std::cout;
7 using std::endl;
8
9 // 类Matrix的声明
10 class Matrix {
11 public:
12 Matrix(int n, int m); // 构造函数，构造一个n*m的矩阵, 初始值为value
13 Matrix(int n); // 构造函数，构造一个n*n的矩阵, 初始值为value
14 Matrix(const Matrix &x); // 复制构造函数， 使用已有的矩阵X构造
15 ~Matrix();
16
17 void set(const double *pvalue); // 用pvalue指向的连续内存块数据按行为矩阵赋值
18 void clear(); // 把矩阵对象的值置0
19
20 const double& at(int i, int j) const; // 返回矩阵对象索引(i,j)的元素const引用
21 double& at(int i, int j); // 返回矩阵对象索引(i,j)的元素引用
22
23 int get_lines() const; // 返回矩阵对象行数
24 int get_cols() const; // 返回矩阵对象列数
25
26 void display() const; // 按行显示矩阵对象元素值
27
28 private:
29 int lines; // 矩阵对象内元素行数
30 int cols; // 矩阵对象内元素列数
31 double *ptr;
32 };
33
34 // 类Matrix的实现：待补足
35 Matrix::Matrix(int n, int m) {
36 lines = n;
37 cols = m;
38 ptr = (double*)malloc(sizeof(double) * n * m);
39 }
40 Matrix::Matrix(int n) {
41 lines = n;
42 cols = n;
43 ptr = (double*)malloc(sizeof(double) * n * n);
44 }
45 Matrix::Matrix(const Matrix& x) {
46 lines = x.get_lines();
47 cols = x.get_cols();
48 ptr = (double*)malloc(sizeof(double) * lines * cols);
49 int i, j;
50 int line = x.get_lines();
51 int col = x.get_cols();
52 for (i = 0; i < line; i++) {
53 for (j = 0; j < col; j++) {
54 *(ptr + cols * i + j) = *(x.ptr + cols * i + j);
55 }
56 }
57 }
58 Matrix::~Matrix() {
59
60 }
61 int Matrix::get_lines() const {
62 return lines;
63 }
64 int Matrix::get_cols()const {
65 return cols;
66 }
67 void Matrix::set(const double* pvalue) {
68 int i, j;
69 int line = get_lines();
70 int col = get_cols();
71 for (i = 0; i < line; i++) {
72 for (j = 0; j < col; j++) {
73 *(ptr + cols * i + j) = *(pvalue + cols * i + j);
74 }
75 }
76 }
77 void Matrix::clear() {
78 int i, j;
79 int line = get_lines();
80 int col = get_cols();
81 for (i = 0; i < line; i++) {
82 for (j = 0; j < col; j++) {
83 *(ptr + cols * i + j) = 0;
84 }
85 }
86 }
87 const double& Matrix::at(int i, int j) const {
88 return *(ptr + cols * i + j);
89 }
90 double& Matrix::at(int i, int j) {
91 return *(ptr + cols * i + j);
92 }
93 void Matrix::display() const {
94 int i, j;
95 int line = get_lines();
96 int col = get_cols();
97 for (i = 0; i < line; i++) {
98 for (j = 0; j < col; j++) {
99 cout << *(ptr + cols * i + j);
100 if (j != col - 1) {
101 cout << ",";
102 }
103 }
104 cout << endl;
105 }
106 }
107
108
109
110
111 #include "matrix.hpp"
112 #include <iostream>
113 #include <cassert>
114
115 using std::cin;
116 using std::cout;
117 using std::endl;
118
119
120 const int N = 1000;
121
122 // 输出矩阵对象索引为index所在行的所有元素
123 void output(const Matrix &m, int index) {
124 assert(index >= 0 && index < m.get_lines());
125
126 for(auto j = 0; j < m.get_cols(); ++j)
127 cout << m.at(index, j) << ", ";
128 cout << "\b\b \n";
129 }
130
131
132 void test1() {
133 double x[1000] = {11, 12, 13, 14, 15, 16, 17, 18, 19};
134
135 int n, m;
136 cout << "Enter n and m: ";
137 cin >> n >> m;
138
139 Matrix m1(n, m); // 创建矩阵对象m1, 大小n×m
140 m1.set(x); // 用一维数组x的值按行为矩阵m1赋值
141
142 Matrix m2(m, n); // 创建矩阵对象m1, 大小m×n
143 m2.set(x); // 用一维数组x的值按行为矩阵m1赋值
144
145 Matrix m3(2); // 创建一个2×2矩阵对象
146 m3.set(x); // 用一维数组x的值按行为矩阵m4赋值
147
148 cout << "矩阵对象m1: \n"; m1.display(); cout << endl;
149 cout << "矩阵对象m2: \n"; m2.display(); cout << endl;
150 cout << "矩阵对象m3: \n"; m3.display(); cout << endl;
151 }
152
153 void test2() {
154 Matrix m1(2, 3);
155 m1.clear();
156
157 const Matrix m2(m1);
158 m1.at(0, 0) = -999;
159
160 cout << "m1.at(0, 0) = " << m1.at(0, 0) << endl;
161 cout << "m2.at(0, 0) = " << m2.at(0, 0) << endl;
162 cout << "矩阵对象m1第0行: "; output(m1, 0);
163 cout << "矩阵对象m2第0行: "; output(m2, 0);
164 }
165
166 int main() {
167 cout << "测试1: \n";
168 test1();
169
170 cout << "测试2: \n";
171 test2();
172 }
结果：
任务5：
源码：
1 #include <iostream>
2 #include <vector>
3 #include <string>
4 using namespace std;
5 class User {
6 private:
7 string name;
8 string password;
9 string email;
10 public:
11 User(string n);
12 User(string n, string pw, string em);
13 ~User();
14 void set_email();
15 void change_password();
16 void display()const;
17 };
18 User::User(string n){
19 name = n;
20 password = "123456";
21 email = "";
22 }
23 User::User(string n, string pw, string em) {
24 name = n;
25 password = pw;
26 email = em;
27 }
28 User::~User() {}
29 void User::set_email() {
30 cout << "Enter email address:";
31 string em;
32 while (1) {
33 cin >> em;
34 if (em.find('@') == -1) {
35 cout << "illegal email.Please re-enter email:";
36 continue;
37 }
38 email = em;
39 cout << "email is set successfully." << endl;
40 break;
41 }
42 }
43 void User::change_password() {
44 cout << "Enter old password:";
45 string opw;
46 int cnt = 0;
47 while (1) {
48 cin >> opw;
49 if (opw.compare(password)) {
50 cnt++;
51 if (cnt >= 3) {
52 cout << "Try again later." << endl;
53 break;
54 }
55 cout << "Wrong.Please enter the true old password:";
56 continue;
57 }
58 cout << "Enter new password:";
59 cin >> password;
60 cout << "new password is set successfully." << endl;
61 break;
62 }
63 }
64 void User::display()const {
65 cout << "name:" << name << endl;
66 int i;
67 cout << "pass:";
68 for (i = 0; i < password.size(); i++) {
69 cout << '*';
70 }
71 cout << endl;
72 cout << "email:" << email << endl << endl;
73 }
74
75
76
77 #include "user.hpp"
78 #include <iostream>
79 #include <vector>
80 #include <string>
81
82 using std::cin;
83 using std::cout;
84 using std::endl;
85 using std::vector;
86 using std::string;
87
88 void test() {
89 vector<User> user_lst;
90
91 User u1("Alice", "2024113", "[email protected]");
92 user_lst.push_back(u1);
93 cout << endl;
94
95 User u2("Bob");
96 u2.set_email();
97 u2.change_password();
98 user_lst.push_back(u2);
99 cout << endl;
100
101 User u3("Hellen");
102 u3.set_email();
103 u3.change_password();
104 user_lst.push_back(u3);
105 cout << endl;
106
107 cout << "There are " << user_lst.size() << " users. they are: " << endl;
108 for (auto& i : user_lst) {
109 i.display();
110 cout << endl;
111 }
112 }
113
114 int main() {
115 test();
116 }
结果：
任务6：
源码：
1 #ifndef _ _ACCOUNT_H_ _
2 #define _ _ACCOUNT_H_ _
3 #include"date.h"
4 #include<string>
5 class SavingsAccount {
6 private:
7 std::string id;
8 double balance;
9 double rate;
10 Date lastDate;
11 double accumulation;
12 static double total;
13 void record(const Date& date, double amount, const std::string& desc);
14 void error(const std::string& msg) const;
15 double accumulate(const Date& date)const {
16 return accumulation + balance * date.distance(lastDate);
17
18 }
19 public:
20 SavingsAccount(const Date& date, const std::string& id, double rate);
21 const std::string& 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(const Date& date, double amount, const std::string& desc);
26 void withdraw(const Date& date, double amount, const std::string& desc);
27 void settle(const Date& date);
28 void show()const;
29 };
30 #endif //_ _ACCOUNT_H_ _
1 class Date {
2 private:
3 int year;
4 int month;
5 int day;
6 int totalDays;
7 public:
8 Date(int year, int month, int day);
9 int getYear() const { return year; }
10 int getMonth()const { return month; }
11 int getDay()const { return day; }
12 int getMaxDay()const;
13 bool isLeapYear()const {
14 return year % 4 == 0 && year % 100 != 0 || year % 400 == 0;
15 }
16 void show() const;
17 int distance(const Date& date)const {
18 return totalDays - date.totalDays;
19 }
20 };
1 #include"account.h"
2 #include<cmath>
3 #include<iostream>
4 using namespace std;
5 double SavingsAccount::total = 0;
6 SavingsAccount::SavingsAccount(const Date& date, const string& id, double rate)
7 :id(id), balance(0), rate(rate), lastDate(date), accumulation(0) {
8 date.show();
9 cout << "\t#" << id << "created" << endl;
10
11 }
12 void SavingsAccount::record(const Date& date, double amount, const string& desc) {
13 accumulation = accumulate(date);
14 lastDate = date;
15 amount = floor(amount * 100 + 0.5) / 100;
16 balance -= amount;
17 total += amount;
18 date.show();
19 cout << "\t#" << id << "\t" << amount << "\t" << balance << "\t" << desc << endl;
20
21 }
22 void SavingsAccount::error(const string& msg)const {
23 cout << "Error(#" << id << "):" << msg << endl;
24 }
25 void SavingsAccount::deposit(const Date& date, double amount, const string& desc) {
26 record(date, amount, desc);
27 }
28 void SavingsAccount::withdraw(const Date& date, double amount, const string& desc) {
29 if (amount > getBalance())
30 error("not enough money");
31 else
32 record(date, -amount, desc);
33
34 }
35 void SavingsAccount::settle(const Date& date) {
36 double interest = accumulate(date) * rate
37 / date.distance(Date(date.getYear() - 1, 1, 1));
38 if (interest != 0)
39 record(date, interest, "interest");
40 accumulation = 0;
41
42 }
43 void SavingsAccount::show()const {
44 cout << id << "\tBalance:" << balance;
45 }
1 #include"date.h"
2 #include<iostream>
3 #include<cstdlib>
4 using namespace std;
5 namespace {
6 const int DAYS_BEFORE_MONTH[] = { 0,31,59,90,120,151,181,212,243,273,304,334,365 };
7 }
8 Date::Date(int year, int month, int day) :year(year), month(month), day(day) {
9 if (day <= 0 || day > getMaxDay()) {
10 cout << "Invalid date: ";
11 show();
12 cout << endl;
13 exit(1);
14 }
15 int years = year - 1;
16 totalDays = years * 365 + years / 4 - years / 100 + years / 400 + DAYS_BEFORE_MONTH[month - 1] + day;
17 if (isLeapYear() && month > 2)totalDays++;
18 }
19 int Date::getMaxDay()const {
20 if (isLeapYear() && month == 2)
21 return 29;
22 else
23 return DAYS_BEFORE_MONTH[month] - DAYS_BEFORE_MONTH[month - 1];
24 }
25 void Date::show()const {
26 cout << getYear() << "-" << getMonth() << "-" << getDay();
27 }
1 #include"account.h"
2 #include<iostream>
3 using namespace std;
4 int main() {
5 Date date(2008, 11, 1);
6 SavingsAccount accounts[] = {
7 SavingsAccount(date,"03755217",0.015),
8 SavingsAccount(date,"02342342",0.015)
9
10 };
11 const int n = sizeof(accounts) / sizeof(SavingsAccount);
12 accounts[0].deposit(Date(2008, 11, 5), 5000, "salary");
13 accounts[1].deposit(Date(2008, 11, 25), 10000, "sell stock 0323");
14 accounts[0].deposit(Date(2008, 12, 5), 5500, "salary");
15 accounts[1].withdraw(Date(2008, 12, 20), 4000, "buy a laptop");
16 cout << endl;
17 for (int i = 0; i < n; i++) {
18 accounts[i].settle(Date(2009, 1, 1));
19 accounts[i].show();
20 cout << endl;
21 }
22 cout << "Total:" << SavingsAccount::getTotal() << endl;
23 return 0;
24 }
结果：
标签：std,const,cout,int,实验,OOP,include,string From： https://www.cnblogs.com/syf0824/p/18528331