实验任务2：

实验代码：

GradeCalc.hpp:

  1 #include <iostream>
  2 #include <vector>
  3 #include <string>
  4 #include <algorithm>
  5 #include <numeric>
  6 #include <iomanip>
  7 
  8 using std::vector;
  9 using std::string;
 10 using std::cin;
 11 using std::cout;
 12 using std::endl;
 13 
 14 class GradeCalc: public vector<int> {
 15 public:
 16     GradeCalc(const string &cname, int size);      
 17     void input();                             // 录入成绩
 18     void output() const;                      // 输出成绩
 19     void sort(bool ascending = false);        // 排序 (默认降序)
 20     int min() const;                          // 返回最低分
 21     int max() const;                          // 返回最高分
 22     float average() const;                    // 返回平均分
 23     void info();                              // 输出课程成绩信息 
 24 
 25 private:
 26     void compute();     // 成绩统计
 27 
 28 private:
 29     string course_name;     // 课程名
 30     int n;                  // 课程人数
 31     vector<int> counts = vector<int>(5, 0);      // 保存各分数段人数（[0, 60), [60, 70), [70, 80), [80, 90), [90, 100]
 32     vector<double> rates = vector<double>(5, 0); // 保存各分数段比例 
 33 };
 34 
 35 GradeCalc::GradeCalc(const string &cname, int size): course_name{cname}, n{size} {}   
 36 
 37 void GradeCalc::input() {
 38     int grade;
 39 
 40     for(int i = 0; i < n; ++i) {
 41         cin >> grade;
 42         this->push_back(grade);
 43     } 
 44 }  
 45 
 46 void GradeCalc::output() const {
 47     for(auto ptr = this->begin(); ptr != this->end(); ++ptr)
 48         cout << *ptr << " ";
 49     cout << endl;
 50 } 
 51 
 52 void GradeCalc::sort(bool ascending) {
 53     if(ascending)
 54         std::sort(this->begin(), this->end());
 55     else
 56         std::sort(this->begin(), this->end(), std::greater<int>());
 57 }  
 58 
 59 int GradeCalc::min() const {
 60     return *std::min_element(this->begin(), this->end());
 61 }  
 62 
 63 int GradeCalc::max() const {
 64     return *std::max_element(this->begin(), this->end());
 65 }    
 66 
 67 float GradeCalc::average() const {
 68     return std::accumulate(this->begin(), this->end(), 0) * 1.0 / n;
 69 }   
 70 
 71 void GradeCalc::compute() {
 72     for(int grade: *this) {
 73         if(grade < 60)
 74             counts.at(0)++;
 75         else if(grade >= 60 && grade < 70)
 76             counts.at(1)++;
 77         else if(grade >= 70 && grade < 80)
 78             counts.at(2)++;
 79         else if(grade >= 80 && grade < 90)
 80             counts.at(3)++;
 81         else if(grade >= 90)
 82             counts.at(4)++;
 83     }
 84 
 85     for(int i = 0; i < rates.size(); ++i)
 86         rates.at(i) = counts.at(i) * 1.0 / n;
 87 }
 88 
 89 void GradeCalc::info()  {
 90     cout << "课程名称:\t" << course_name << endl;
 91     cout << "排序后成绩: \t";
 92     sort();  output();
 93     cout << "最高分:\t" << max() << endl;
 94     cout << "最低分:\t" << min() << endl;
 95     cout << "平均分:\t" << std::fixed << std::setprecision(2) << average() << endl;
 96     
 97     compute();  // 统计各分数段人数、比例
 98 
 99     vector<string> tmp{"[0, 60)  ", "[60, 70)", "[70, 80)","[80, 90)", "[90, 100]"};
100     for(int i = tmp.size()-1; i >= 0; --i)
101         cout << tmp[i] << "\t: " << counts[i] << "人\t" 
102              << std::fixed << std::setprecision(2) << rates[i]*100 << "%" << endl; 
103 }
View Code

demo2.cpp:

 1 #include "GradeCalc.hpp"
 2 #include <iomanip>
 3 
 4 void test() {
 5     int n;
 6     cout << "输入班级人数: ";
 7     cin >> n;
 8 
 9     GradeCalc c1("OOP", n);
10 
11     cout << "录入成绩: " << endl;;
12     c1.input();
13     cout << "输出成绩: " << endl;
14     c1.output();
15 
16     cout << string(20, '*') + "课程成绩信息"  + string(20, '*') << endl;
17     c1.info();
18 }
19 
20 int main() {
21     test();
22 }
View Code

实验截图：

问题1：储存在GradeCalc继承的基类vector<int>grade中；通过public继承方式继承的vector自带的接口访问成绩，输入成绩。
问题2：分母的作用：计算平均值；去掉1.0，编译结果有影响，accumulate作为继承vector自带的接口，数据类型为整型，整除后结果仍为整型数据，乘1.0将数据类型转换为浮点型。
问题3：未能做到将成绩与具体的学生对应；对输入错误的数据不能正确进行反馈。

 

实验任务3：

实验代码：

GradeCalc.hpp:

  1 #include <iostream>
  2 #include <vector>
  3 #include <string>
  4 #include <algorithm>
  5 #include <numeric>
  6 #include <iomanip>
  7 
  8 using std::vector;
  9 using std::string;
 10 using std::cin;
 11 using std::cout;
 12 using std::endl;
 13 
 14 class GradeCalc {
 15 public:
 16     GradeCalc(const string &cname, int size);      
 17     void input();                             // 录入成绩
 18     void output() const;                      // 输出成绩
 19     void sort(bool ascending = false);        // 排序 (默认降序)
 20     int min() const;                          // 返回最低分
 21     int max() const;                          // 返回最高分
 22     float average() const;                    // 返回平均分
 23     void info();                              // 输出课程成绩信息 
 24 
 25 private:
 26     void compute();     // 成绩统计
 27 
 28 private:
 29     string course_name;     // 课程名
 30     int n;                  // 课程人数
 31     vector<int> grades;     // 课程成绩
 32     vector<int> counts = vector<int>(5, 0);      // 保存各分数段人数（[0, 60), [60, 70), [70, 80), [80, 90), [90, 100]
 33     vector<double> rates = vector<double>(5, 0); // 保存各分数段比例 
 34 };
 35 
 36 GradeCalc::GradeCalc(const string &cname, int size): course_name{cname}, n{size} {}   
 37 
 38 void GradeCalc::input() {
 39     int grade;
 40 
 41     for(int i = 0; i < n; ++i) {
 42         cin >> grade;
 43         grades.push_back(grade);
 44     } 
 45 }  
 46 
 47 void GradeCalc::output() const {
 48     for(int grade: grades)
 49         cout << grade << " ";
 50     cout << endl;
 51 } 
 52 
 53 void GradeCalc::sort(bool ascending) {
 54     if(ascending)
 55         std::sort(grades.begin(), grades.end());
 56     else
 57         std::sort(grades.begin(), grades.end(), std::greater<int>());
 58         
 59 }  
 60 
 61 int GradeCalc::min() const {
 62     return *std::min_element(grades.begin(), grades.end());
 63 }  
 64 
 65 int GradeCalc::max() const {
 66     return *std::max_element(grades.begin(), grades.end());
 67 }    
 68 
 69 float GradeCalc::average() const {
 70     return std::accumulate(grades.begin(), grades.end(), 0) * 1.0 / n;
 71 }   
 72 
 73 void GradeCalc::compute() {
 74     for(int grade: grades) {
 75         if(grade < 60)
 76             counts.at(0)++;
 77         else if(grade >= 60 && grade < 70)
 78             counts.at(1)++;
 79         else if(grade >= 70 && grade < 80)
 80             counts.at(2)++;
 81         else if(grade >= 80 && grade < 90)
 82             counts.at(3)++;
 83         else if(grade >= 90)
 84             counts.at(4)++;
 85     }
 86 
 87     for(int i = 0; i < rates.size(); ++i)
 88         rates.at(i) = counts.at(i) *1.0 / n;
 89 }
 90 
 91 void GradeCalc::info()  {
 92     cout << "课程名称:\t" << course_name << endl;
 93     cout << "排序后成绩: \t";
 94     sort();  output();
 95     cout << "最高分:\t" << max() << endl;
 96     cout << "最低分:\t" << min() << endl;
 97     cout << "平均分:\t" << std::fixed << std::setprecision(2) << average() << endl;
 98     
 99     compute();  // 统计各分数段人数、比例
100 
101     vector<string> tmp{"[0, 60)  ", "[60, 70)", "[70, 80)","[80, 90)", "[90, 100]"};
102     for(int i = tmp.size()-1; i >= 0; --i)
103         cout << tmp[i] << "\t: " << counts[i] << "人\t" 
104              << std::fixed << std::setprecision(2) << rates[i]*100 << "%" << endl; 
105 }
View Code

demo3.cpp:

 1 #include "GradeCalc.hpp"
 2 #include <iomanip>
 3 
 4 void test() {
 5     int n;
 6     cout << "输入班级人数: ";
 7     cin >> n;
 8 
 9     GradeCalc c1("OOP", n);
10 
11     cout << "录入成绩: " << endl;;
12     c1.input();
13     cout << "输出成绩: " << endl;
14     c1.output();
15 
16     cout << string(20, '*') + "课程成绩信息"  + string(20, '*') << endl;
17     c1.info();
18 }
19 
20 int main() {
21     test();
22 }
View Code

实验截图：

问题1：储存在GradeCalc类的私有成员vector<int> grades中；访问类中的私有成员grades。
问题2：在自定义类时，既可以和基类继承，也可以和基类进行组合。

 

实验任务4：

实验代码：

task4_1.cpp:

 1 #include <iostream>
 2 #include <string>
 3 #include <limits>
 4 
 5 using namespace std;
 6 
 7 void test1() {
 8     string s1, s2;
 9     cin >> s1 >> s2;  // cin: 从输入流读取字符串, 碰到空白符(空格/回车/Tab)即结束
10     cout << "s1: " << s1 << endl;
11     cout << "s2: " << s2 << endl;
12 }
13 
14 void test2() {
15     string s1, s2;
16     getline(cin, s1);  // getline(): 从输入流中提取字符串，直到遇到换行符
17     getline(cin, s2);
18     cout << "s1: " << s1 << endl;
19     cout << "s2: " << s2 << endl;
20 }
21 
22 void test3() {
23     string s1, s2;
24     getline(cin, s1, ' '); //从输入流中提取字符串，直到遇到指定分隔符
25     getline(cin, s2);
26     cout << "s1: " << s1 << endl;
27     cout << "s2: " << s2 << endl;
28 }
29 
30 int main() {
31     cout << "测试1: 使用标准输入流对象cin输入字符串" << endl;
32     test1();
33     cout << endl;
34 
35     cin.ignore(numeric_limits<streamsize>::max(), '\n');
36 
37     cout << "测试2: 使用函数getline()输入字符串" << endl;
38     test2();
39     cout << endl;
40 
41     cout << "测试3: 使用函数getline()输入字符串, 指定字符串分隔符" << endl;
42     test3();
43 }
View Code

task4_2.cpp:

 1 #include <iostream>
 2 #include <string>
 3 #include <vector>
 4 #include <limits>
 5 
 6 using namespace std;
 7 
 8 void output(const vector<string> &v) {
 9     for(auto &s: v)
10         cout << s << endl;
11 }
12 
13 void test() {
14     int n;
15     while(cout << "Enter n: ", cin >> n) {
16         vector<string> v1;
17 
18         for(int i = 0; i < n; ++i) {
19             string s;
20             cin >> s;
21             v1.push_back(s);
22         }
23 
24         cout << "output v1: " << endl;
25         output(v1); 
26         cout << endl;
27     }
28 }
29 
30 int main() {
31     cout << "测试: 使用cin多组输入字符串" << endl;
32     test();
33 }
View Code

task4_3.cpp:

 1 #include <iostream>
 2 #include <string>
 3 #include <vector>
 4 #include <limits>
 5 
 6 using namespace std;
 7 
 8 void output(const vector<string> &v) {
 9     for(auto &s: v)
10         cout << s << endl;
11 }
12 
13 void test() {
14     int n;
15     while(cout << "Enter n: ", cin >> n) {
16         cin.ignore(numeric_limits<streamsize>::max(), '\n');
17 
18         vector<string> v2;
19 
20         for(int i = 0; i < n; ++i) {
21             string s;
22             getline(cin, s);
23             v2.push_back(s);
24         }
25         cout << "output v2: " << endl;
26         output(v2); 
27         cout << endl;
28     }
29 }
30 
31 int main() {
32     cout << "测试: 使用函数getline()多组输入字符串" << endl;
33     test();
34 }
View Code

实验截图：

问题1 / 2：在输入操作中忽略从标准输入流 cin 中读取的多余字符，直到遇到换行符 \n 为止。这个函数常用于清理输入缓冲区，以避免在接下来的输入操作中出现意外的输入。

 

实验任务5：

实验代码：

grm.hpp:

 1 #pragma once
 2 
 3 #include <iostream>
 4 
 5 using namespac std;
 6 
 7 template<typename T>
 8 class GameResourceManager {
 9 public:
10     GameResourceManager(T Resource):resource(Resource) {}
11     T get()const {
12         return resource;
13     }
14     void update(T num) {
15         resource += num;
16         if(resource < 0) resource = 0;
17     }
18 private:
19     T resource;
20 };
View Code

grm.cpp:

 1 #include "grm.hpp"
 2 #include <iostream>
 3 
 4 using std::cout;
 5 using std::endl;
 6 
 7 void test1() {
 8     GameResourceManager<float> HP_manager(99.99);
 9     cout << "当前生命值: " << HP_manager.get() << endl;
10     HP_manager.update(9.99);
11     cout << "增加9.99生命值后, 当前生命值: " << HP_manager.get() << endl;
12     HP_manager.update(-999.99);
13     cout <<"减少999.99生命值后, 当前生命值: " << HP_manager.get() << endl;
14 }
15 
16 void test2() {
17     GameResourceManager<int> Gold_manager(100);
18     cout << "当前金币数量: " << Gold_manager.get() << endl;
19     Gold_manager.update(50);
20     cout << "增加50个金币后, 当前金币数量: " << Gold_manager.get() << endl;
21     Gold_manager.update(-99);
22     cout <<"减少99个金币后, 当前金币数量: " << Gold_manager.get() << endl;
23 }
24 
25 
26 int main() {
27     cout << "测试1: 用float类型对类模板GameResourceManager实例化" << endl;
28     test1();
29     cout << endl;
30 
31     cout << "测试2: 用int类型对类模板GameResourceManager实例化" << endl;
32     test2();
33 }
View Code

实验截图：

 

实验任务6：

实验代码：

info.hpp:

 1 #pragma once
 2 
 3 #include <iostream>
 4 #include <string>
 5 #include <iomanip>
 6 
 7 using namespace std;
 8 
 9 class Info {
10 public:
11     Info(string nickname0, string contact0, string city0, int n0) : 
12         nickname{nickname0}, contact{contact0}, city{city0}, n{n0} {}
13     void display() const {
14         cout << string(40, '-') << endl;
15         cout << "昵称：" << "\t" << nickname << endl;
16         cout << "联系方式：" << "\t" << contact << endl;
17         cout << "所在城市：" << "\t" << city << endl;
18         cout << "预定人数：" << "\t" << n << endl;
19     }
20 private:
21     string nickname;
22     string contact;
23     string city;
24     int n;
25 };
View Code

task6.cpp:

 1 #include "Info.hpp"
 2 #include <vector>
 3 
 4 const int capacity = 100;
 5 
 6 void task6() {
 7     cout << "录入用户预约信息：" << endl;
 8     cout << endl;
 9     cout << "昵称" << "\t" << "联系方式（邮箱/手机号）" << "\t" << "所在城市" << "\t" << "预定参加人数" << endl;
10     vector<Info> audience_lst;
11     string nickname, contact, city;
12     int num;
13     int sum = 0;
14     while(cin >> nickname >> contact >> city >> num) {
15         audience_lst.push_back(Info(nickname, contact, city, num));
16         sum += num;
17         if(sum == capacity)
18             break;
19         if(sum > capacity) {
20             sum -= num;
21             audience_lst.pop_back();
22             char choice;
23             cout << "对不起，只剩" << capacity - sum << "个位置." << endl;
24             cout << "1. 输入u，更新（update）预定信息" << endl;
25             cout << "2. 输入q， 退出预定" << endl;
26             cout << "你的选择：";
27             cin >> choice;
28             if (choice == 'u') {
29                 cout << "请重新输入预定信息：" << endl;
30                 continue;
31             }
32             else if(choice == 'q')
33                 break; 
34         }
35     }
36     cout << "截至目前，一共有" << sum << "位听众预约。" << "预约听众信息如下：" << endl;
37     for(auto i : audience_lst) {
38         i.display();
39     }
40     cout << string(40, '-'); 
41 }
42 
43 int main() {
44     task6();
45     return 0;
46 }
View Code

实验截图：

 

实验任务7：

实验代码：

date.h:

 1 #pragma once
 2 class Date {
 3 private:
 4     int year;
 5     int month;
 6     int day;
 7     int totalDays;
 8 public:
 9     Date(int year, int month, int day);
10     int getYear() const {return year;}
11     int getMonth() const {return month;}
12     int getDay() const {return day;}
13     int getMaxDay() const;
14     bool isLeapYear() const {
15         return year%4==0 && year%100 != 0 || year%400==0;
16     }
17     void show() const;
18 
19     int distance(const Date& date) const {
20         return totalDays-date.totalDays;
21     }
22 };
View Code

date.cpp:

 1 #include "date.h"
 2 #include<iostream>
 3 #include<cstdlib>
 4 using namespace std;
 5 namespace {
 6     const int DAYS_BEFIRE_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
17         + DAYS_BEFIRE_MONTH[month - 1] + day;
18     if (isLeapYear() && month > 2) totalDays++;
19     }
20     int Date::getMaxDay()const {
21         if (isLeapYear() &&month == 2)
22             return 29;
23         else
24             return DAYS_BEFIRE_MONTH[month] - DAYS_BEFIRE_MONTH[month - 1];
25     }
26     void Date::show()const {
27         cout << getYear() << "-" << getMonth() << "-" << getDay();
28     }
View Code

accumulator.h:

 1 #include "date.h"
 2 class Accumulator {
 3 private:
 4     Date lastDate;
 5     double value;
 6     double sum;
 7 public:
 8     Accumulator(const Date&date,double value):lastDate(date),value(value),sum{0}{}
 9     double getSum(const Date& date) const {
10         return sum + value * date.distance(lastDate);
11     }
12     void change(const Date& date, double value) {
13         sum = getSum(date);
14         lastDate = date;
15         this->value = value;
16     }
17     void reset(const Date& date, double value) {
18         lastDate = date;
19         this->value;
20         sum = 0;
21     }
22 };
View Code

account.h:

 1 #include"date.h"
 2 #include"accumulator.h"
 3 #include<string>
 4 using namespace std;
 5 class Account {
 6 private:
 7     string id;
 8     double balance;
 9     static double total;
10 protected:
11     Account(const Date& date, const string &id);
12     void record(const Date& date, double amount, const string& desc);
13     void error(const string& msg) const;
14 public:const string& getId() { return id; }
15     double getBalance()const { return balance; }
16     static double getTotal() { return total; }
17     void show()const;
18 };
19 class SavingsAccount:public Account {
20 private:
21     Accumulator acc;
22     double rate;
23 public:
24     SavingsAccount(const Date& date, const string& id, double rate);
25     double getRate() const { return  rate; }
26     void deposit(const Date& date, double amount, const string& desc);
27     void withdraw(const Date& date, double amount, const string& desc);
28     void settle(const Date& date);
29 };
30 class CreditAccount :public Account {
31 private:
32     Accumulator acc;
33     double credit;
34     double rate;
35     double fee;
36     double getDebt()const {
37         double balance = getBalance();
38         return(balance < 0 ? balance : 0);
39     }
40 public:CreditAccount(const Date& date, const string& id, double credit, double rate, double fee);
41     double getCredit()const { return credit; }
42     double getRate()const { return rate; }
43     double getFee() const { return fee; }
44     double getAvailableCredit()const {
45         if (getBalance() < 0)return credit + getBalance();
46         else return credit;
47     }
48     void deposit(const Date& date, double amount, const string& desc);
49     void withdraw(const Date& date, double amount, const string& desc);
50     void settle(const Date& date);
51     void show()const;
52 };
View Code

account.cpp:

 1 #include "account.h"
 2 #include<iostream>
 3 using namespace std;
 4 int main() {
 5     Date date(2008, 11, 1);
 6     SavingsAccount sa1(date, "S3755217", 0.015);
 7     SavingsAccount sa2(date, "02342342", 0.015);
 8     CreditAccount ca(date, "C5392394", 10000, 0.0005, 50);
 9     sa1.deposit(Date(2008, 11, 5), 5000, "Salary");
10     ca.withdraw(Date(2008, 11, 15), 2000, "buy a cell");
11     sa2.deposit(Date(2008, 11, 25), 10000, "sell stock 0323");
12     ca.settle(Date(2008, 12, 1));
13     ca.deposit(Date(2008, 12,1), 2016, "repay the credit");
14     sa1.deposit(Date(2008, 12, 5), 5500, "salary");
15     sa1.settle(Date(2009, 1, 1));
16     sa2.settle(Date(2009, 1, 1));
17     ca.settle(Date(2009, 1, 1));
18     cout << endl;
19     sa1.show(); cout << endl;
20     sa2.show(); cout << endl;
21     ca.show(); cout << endl;
22     cout << "Total: " << Account::getTotal() << endl;
23     return 0; 
24 }
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实验截图：

改进：每个派生类都将基类的成员原样继承过来，因此无需为每个派生类重复定义数据成员和相应的获取函数

问题：两个派生类SavingsAccount和CreditAccount虽然具有相同的成员函数，但由于其实现不同，只能在派生类中给出它们的实现，因而它们是彼此独立的函数，不能将三个账户放在一个数组里进行操作。