实验4 类的组合、继承、模板类、标准库

实验任务2：

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 }

task2.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 }

运行结果截图

问题1：成绩存储在派生类GradeCalc容器中。通过this对象本身接口begin和end，input通过push_back接口。

问题2：确定精度，有影响，乘1.0后精度为小数点后一位

问题3：vector的派生类，基于迭代器，耦合度高。

实验任务3

GradeCallc.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

task.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

运行结果图：

问题1：

存储在grades对象中，通过grades访问。

问题2：高内聚低耦合，灵活性。

实验任务4

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

问题1：

函数用于忽略输入流中的字符，直到遇到指定的终止字符。

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

运行结果截图：

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

运行结果截图：

问题2：

函数用于忽略输入流中的字符，直到遇到指定的终止字符。

实验任务5：

grm.hpp

 1 #pragma once
 2 #include<iostream>
 3 
 4 using namespace std;
 5 
 6 template<typename T>
 7 class GameResourceManager{
 8     public:
 9         GameResourceManager(T resource0);
10         T get()const;
11         void update(T resource1);
12     private:
13         T resource;
14 }; 
15 template<typename T>
16 GameResourceManager<T>::GameResourceManager(T resource0):resource(resource0){}
17 template<typename T>
18 T GameResourceManager<T>::get()const{
19     return this->resource;
20 }
21 template<typename T>
22 void GameResourceManager<T>::update(T resource1){
23     resource += resource1;
24     if(resource<0)resource=0;
25 }

View Code

 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

运行结果截图：

实验任务6：

info.hpp

 1 #include<iostream>
 2 #include<string>
 3 #include <iomanip>
 4 
 5 using namespace std;
 6 class Info{
 7     public:
 8         Info(const string &nic,const string &con,const string &cit,int n0):nickname(nic),contact(con),city(cit),n(n0){
 9         };
10         void display(){
11             string s(30,'-');
12             cout<< s << endl ;
13             cout<< setw(10) << "昵称" << nickname << endl;
14             cout<< setw(10) << "联系方式" << contact << endl;
15             cout<< setw(10) << "所在城市" << city << endl;
16             cout<< setw(10) << "预定人数" << n << endl;
17         };
18     private:
19         string nickname; //昵称 
20         string contact; //联系方式 
21         string city;  //所在城市 
22         int n; //人数 
23 };

View Code

task6.cpp

 1 #include"info.hpp"
 2 #include<iostream>
 3 #include<string>
 4 #include<vector>
 5 #include <iomanip>
 6 
 7 using namespace std;
 8 int main()
 9 {    //存放最多能容纳的听众人数 
10     const int capacity=100;
11     //存放线上预约登记的所有听众信息 
12     vector<Info> audience_lst;
13     char choice;string nickname,contact,city;int n;
14     cout<<"录入用户预约信息：\n"<<endl;
15     cout<<"昵称"<<setw(30)<<"联系方式（邮箱/手机号）"<<setw(20)<<"所在城市"<<setw(20)<<"预定参加人数"<<endl;
16     int i=0,sum=0;
17     while((cin>>nickname>>contact>>city>>n))
18     {
19         audience_lst.push_back(Info(nickname,contact,city,n));
20         sum+=n;
21         i++;
22         if(sum>capacity)
23        {
24            sum-=n;
25         cout<<"对不起，只剩"<<capacity-sum<<"个位置。\n";
26         cout<<"1.输入u,更新（update）预定信息\n";
27         cout<<"2.输入q,退出预定\n";
28         cout<<"你的选择：";
29         cin>>choice;
30         if(choice=='u')
31         {
32             cout<<"请重新输入预定信息：\n";
33             i--;
34             continue;
35         }
36         else
37         {
38             break;
39         }
40        }
41 
42     }
43 
44     cout<<"截至目前，一共有"<<sum<<"位听众预约。预约听众信息如下：\n";
45     for(int j=0;j<i;j++)
46     {
47         audience_lst[j].display();
48     }
49 }

View Code

运行结果截图：

实验任务7：

date.h

 1 #pragma once
 2 
 3 class Date {
 4 private:
 5     int year;
 6     int month;
 7     int day;
 8     int totalDays;
 9 public:
10     Date(int year,int month,int day);
11     int getYear() const {return year;}
12     int getMonth() const {return month;}
13     int getDay() const {return day;}
14     int getMaxDay() const;
15     bool isLeapYear() const {
16         return year%4 ==0 && year%100 !=0 || year%400==0;
17     }
18     void show() const;
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 
 5 using namespace std;
 6 
 7 namespace {
 8     const int DAYS_BEFIRE_MONTH[] = { 0,31,59,90,120,151,181,212,243,273,304 ,334,365 };
 9 }
10 Date::Date(int year, int month, int day) :year(year), month(month), day(day) {
11     if (day<= 0 || day>getMaxDay()) {
12         cout<<"Invalid date: ";
13         show();
14         cout<<endl;
15         exit(1);
16     }
17     int years=year-1;
18     totalDays=years*365+years/4-years/100+years/400+DAYS_BEFIRE_MONTH[month-1]+day;
19     if (isLeapYear() && month>2) totalDays++;
20 }
21 int Date::getMaxDay() const {
22     if (isLeapYear() &&month==2)
23          return 29;
24     else 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 = value;
20         sum = 0;
21     }
22 };

View Code

accumnt.h

 1 #include "date.h"
 2 #include "accumulator.h"
 3 #include <string>
 4 
 5 using namespace std;
 6 
 7 class Account {
 8 private:
 9     string id;
10     double balance;
11     static double total;
12 protected:
13     Account(const Date &date , const string &id);
14     void record(const Date &date , double amount , const string &desc);
15     void error(const string &msg) const;
16 public:
17     const string getId() const {return id;}
18     double getBalance() const {return balance;}
19     static double getTotal() {return total;}
20     void show() const;
21 };
22 class SavingsAccount:public Account {
23 private:
24     Accumulator acc;
25     double rate;
26 public:
27     SavingsAccount(const Date& date , const string& id , double rate);
28     double getRate() const {return rate;}
29     void deposit(const Date& date , double amount , const string& desc);
30     void withdraw(const Date& date , double amount , const string& desc);
31     void settle(const Date& date);
32 };
33 class CreditAccount :public Account {
34 private:
35     Accumulator acc;
36     double credit;
37     double rate;
38     double fee;
39     double getDebt() const {
40         double balance = getBalance();
41         return(balance < 0 ? balance : 0);
42     }
43 public:CreditAccount(const Date& date , const string& id , double credit , double rate , double fee);
44       double getCredit() const {return credit;}
45       double getRate() const {return rate;}
46       double getFee() const {return fee;}
47       double getAvailableCredit() const {
48           if (getBalance() < 0) return credit + getBalance();
49           else return credit;
50       }
51       void deposit(const Date& date , double amount , const string& desc);
52       void withdraw(const Date& date , double amount , const string& desc);
53       void settle(const Date& date);
54       void show() const;
55 };

View Code

account.cpp

 1 #include "account.h"
 2 #include <cmath>
 3 #include<iostream>
 4 using namespace std;
 5 double Account::total = 0;
 6 Account::Account(const Date& date, const string& id) :id(id), balance(0) {
 7     date.show();
 8     cout << "\t#" << id << "created" << endl;
 9 }
10 void Account::record(const Date& date, double amount, const string& desc) {
11     amount = floor(amount * 100 + 0.5) / 100;
12     balance += amount;
13     total += amount;
14     date.show();
15     cout << "\t#" << id << "\t" << amount << "\t" << balance << "\t" << desc << endl;
16 }
17 void Account::show() const { cout << id << "\tBalance:" << balance; }
18 void Account::error(const string& msg) const {
19     cout << "Error(#" << id << "):" << msg << endl;
20 }
21 SavingsAccount::SavingsAccount(const Date&date,const string &id,double rate):Account(date,id),rate(rate),acc(date,0){}
22 void SavingsAccount::deposit(const Date& date, double amount, const string& desc) {
23     record(date, amount, desc);
24     acc.change(date, getBalance());
25 }
26 void SavingsAccount::withdraw(const Date& date, double amount, const string& desc) {
27     if (amount > getBalance()) {
28         error("not enough money");
29     }
30     else {
31         record(date, -amount, desc);
32         acc.change(date, getBalance());
33     }
34 }
35 void SavingsAccount::settle(const Date& date) {
36     double interest = acc.getSum(date) * rate/date.distance(Date(date.getYear()-1,1,1));
37     if (interest != 0)record(date, interest, "interest");
38     acc.reset(date, getBalance());
39 }
40 CreditAccount::CreditAccount(const Date&date,const string &id,double credit,double rate,double fee):Account(date,id),credit(credit),rate(rate),fee(fee),acc(date,0){}
41 void CreditAccount::deposit(const Date& date, double amount, const string& desc) {
42     record(date, amount, desc);
43     acc.change(date, getDebt());
44 }
45 void CreditAccount::withdraw(const Date& date, double amount, const string& desc) {
46     if (amount - getBalance() > credit) {
47         error("not enouogh credit");
48     }
49     else {
50         record(date, -amount, desc);
51         acc.change(date, getDebt());
52     }
53 }
54 void CreditAccount::settle(const Date& date) {
55     double interest = acc.getSum(date) * rate;
56     if (interest != 0) record(date, interest, "interest");
57     if (date.getMonth() == 1)record(date, -fee, "annual fee");
58     acc.reset(date, getDebt());
59 }
60 void CreditAccount::show() const {
61     Account::show();
62     cout << "\tAvailable credit:" << getAvailableCredit();
63 }

View Code

7_10.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 }