实验4 类的组合、继承、模板类、标准库
task2：
代码：
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 }
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 }
截图：
问题1：
成绩存储在：通过this指针存在push_back（grade）中；通过this指针进行访问
问题2：
作用：对于班级总成绩进行求平均，同时明确输出的平均值为float型数据，没有影响，作用是将整型的总成绩变为浮点型数据
问题3：
对于各分数段成绩的统计，对于总分不同的成绩统计不太适用
task3：
代码：
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 }
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 }
截图：
问题1：
直接存储到了<vector>grades 当中；
是通过grades直接访问，减少了对this->指针的使用
问题2：
实验三对于成绩的存储，直接选用增加一个<vector>grades直接存入成绩，更加方便，直接
task4.1:
代码：
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 }
截图：
问题1：作用：防止test1最后输入的换行操作对test2产生影响。
task4.2:
代码：
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 }
截图：
task4.3：
代码：
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 }
截图：
问题：
用途：消除上一次测试对本次测试的影响。
task 5:
代码：
1 hpp
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 }
task6:
代码：
1 hpp 2 #pragma once 3 #include<iostream> 4 #include<iomanip> 5 using namespace std; 6 class Info { 7 public: 8 string nickname; 9 string contact; 10 string city; 11 int n; 12 public: 13 Info(string nickname_,string contact_,string city_,int n_):nickname(nickname_),contact(contact_),city(city_), n(n_) {} 14 void display()const { 15 cout << string(40, '*') << endl; 16 cout << "昵称:" << "\t" << nickname << endl; 17 cout << "联系方式:" << "\t" << contact << endl; 18 cout << "所在城市:" << "\t" << city << endl; 19 cout << "预定人数:" << "\t" << n << endl; 20 } 21 };
1 cpp 2 #include"Info.hpp" 3 #include<iomanip> 4 #include<vector> 5 const int capacity = 100; 6 int main() { 7 cout << "录入用户预约信息:" << endl; 8 cout << "录入用户数:"; 9 int n; 10 cin >> n; 11 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; 12 vector<Info> v; 13 string nickname; 14 string contact; 15 string city; 16 int num; 17 int sum = 0; 18 for (int i = 0; i < n; i++) { 19 cin >> nickname >> contact >> city >> num; 20 sum += num; 21 if (sum > capacity) { 22 char choice; 23 cout << "对不起，只剩" << 100 + num - 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 sum -= num; 30 cout << "请重新输入预定信息" << endl; 31 cin >> nickname >> contact >> city >> num; 32 sum += num; 33 } 34 else if(choice=='q') { 35 continue; 36 } 37 } 38 v.push_back(Info(nickname, contact, city, num)); 39 } 40 cout << "截至目前,一共有" << sum << "位听众预约。" << "预约听众信息如下:" << endl; 41 for (auto i : v) { 42 i.display(); 43 } 44 cout << string(40, '*'); 45 return 0; 46 }
截图：
task7:
代码：
1 date.h 2 #pragma once 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 }; 23 accumulator.h 24 #pragma once 25 #include "date.h" 26 class Accumulator { 27 private: 28 Date lastDate; 29 double value; 30 double sum; 31 public: 32 Accumulator(const Date&date,double value):lastDate(date),value(value),sum{0}{} 33 double getSum(const Date& date) const { 34 return sum + value * date.distance(lastDate); 35 } 36 void change(const Date& date, double value) { 37 sum = getSum(date); 38 lastDate = date; 39 this->value = value; 40 } 41 void reset(const Date& date, double value) { 42 lastDate = date; 43 this->value; 44 sum = 0; 45 } 46 }; 47 account.h 48 #pragma once 49 #include"date.h" 50 #include"accumulator.h" 51 #include<string> 52 using namespace std; 53 class Account { 54 private: 55 string id; 56 double balance; 57 static double total; 58 protected: 59 Account(const Date& date, const string &id); 60 void record(const Date& date, double amount, const string& desc); 61 void error(const string& msg) const; 62 public:const string& getId() { return id; } 63 double getBalance()const { return balance; } 64 static double getTotal() { return total; } 65 void show()const; 66 }; 67 class SavingsAccount:public Account { 68 private: 69 Accumulator acc; 70 double rate; 71 public: 72 SavingsAccount(const Date& date, const string& id, double rate); 73 double getRate() const { return rate; } 74 void deposit(const Date& date, double amount, const string& desc); 75 void withdraw(const Date& date, double amount, const string& desc); 76 void settle(const Date& date); 77 }; 78 class CreditAccount :public Account { 79 private: 80 Accumulator acc; 81 double credit; 82 double rate; 83 double fee; 84 double getDebt()const { 85 double balance = getBalance(); 86 return(balance < 0 ? balance : 0); 87 } 88 public:CreditAccount(const Date& date, const string& id, double credit, double rate, double fee); 89 double getCredit()const { return credit; } 90 double getRate()const { return rate; } 91 double getFee() const { return fee; } 92 double getAvailableCredit()const { 93 if (getBalance() < 0)return credit + getBalance(); 94 else return credit; 95 } 96 void deposit(const Date& date, double amount, const string& desc); 97 void withdraw(const Date& date, double amount, const string& desc); 98 void settle(const Date& date); 99 void show()const; 100 }; 101 102 date.cpp 103 #include"date.h" 104 #include<iostream> 105 #include<cstdlib> 106 using namespace std; 107 namespace { 108 const int DAYS_BEFIRE_MONTH[] = { 0,31,59,90,120,151,181,212,243,273,304 ,334,365 }; 109 } 110 Date::Date(int year, int month, int day) :year(year), month(month), day(day) { 111 if (day <= 0 || day > getMaxDay()) { 112 cout << "Invalid date: "; 113 show(); 114 cout << endl; 115 exit(1); 116 } 117 int years = year - 1; 118 totalDays = years * 365 + years / 4 - years / 100 + years / 400 + DAYS_BEFIRE_MONTH[month - 1] + day; 119 if (isLeapYear() && month > 2) totalDays++; 120 } 121 int Date::getMaxDay()const { 122 if (isLeapYear() && month == 2) 123 return 29; 124 else return DAYS_BEFIRE_MONTH[month] - DAYS_BEFIRE_MONTH[month - 1]; 125 } 126 void Date::show()const { 127 cout << getYear() << "-" << getMonth() << "-" << getDay(); 128 } 129 130 accumulator.cpp 131 #include "account.h" 132 #include <cmath> 133 #include<iostream> 134 using namespace std; 135 double Account::total = 0; 136 Account::Account(const Date& date, const string& id) :id(id), balance(0) { 137 date.show(); 138 cout << "\t#" << id << "created" << endl; 139 } 140 void Account::record(const Date& date, double amount, const string& desc) { 141 amount = floor(amount * 100 + 0.5) / 100; 142 balance += amount; 143 total += amount; 144 date.show(); 145 cout << "\t#" << id << "\t" << amount << "\t" << balance << "\t" << desc << endl; 146 } 147 void Account::show()const { cout << id << "\tBalance:" << balance; } 148 void Account::error(const string& msg)const { 149 cout << "Error(#" << id << "):" << msg << endl; 150 } 151 SavingsAccount::SavingsAccount(const Date&date,const string &id,double rate):Account(date,id),rate(rate),acc(date,0){} 152 void SavingsAccount::deposit(const Date& date, double amount, const string& desc) { 153 record(date, amount, desc); 154 acc.change(date, getBalance()); 155 } 156 void SavingsAccount::withdraw(const Date& date, double amount, const string& desc) { 157 if (amount > getBalance()) { 158 error("not enough money"); 159 } 160 else { 161 record(date, -amount, desc); 162 acc.change(date, getBalance()); 163 } 164 } 165 void SavingsAccount::settle(const Date& date) { 166 double interest = acc.getSum(date) * rate/date.distance(Date(date.getYear()-1,1,1)); 167 if (interest != 0)record(date, interest, "interest"); 168 acc.reset(date, getBalance()); 169 } 170 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){} 171 void CreditAccount::deposit(const Date& date, double amount, const string& desc) { 172 record(date, amount, desc); 173 acc.change(date, getDebt()); 174 } 175 void CreditAccount::withdraw(const Date& date, double amount, const string& desc) { 176 if (amount - getBalance() > credit) { 177 error("not enouogh credit"); 178 } 179 else { 180 record(date, -amount, desc); 181 acc.change(date, getDebt()); 182 } 183 } 184 void CreditAccount::settle(const Date& date) { 185 double interest = acc.getSum(date) * rate; 186 if (interest != 0) record(date, interest, "interest"); 187 if (date.getMonth() == 1)record(date, -fee, "annual fee"); 188 acc.reset(date, getDebt()); 189 } 190 void CreditAccount::show()const { 191 Account::show(); 192 cout << "\tAvailable credit:" << getAvailableCredit(); 193 } 194 task7.cpp 195 #include "account.h" 196 #include<iostream> 197 using namespace std; 198 int main() { 199 Date date(2008, 11, 1); 200 SavingsAccount sa1(date, "S3755217", 0.015); 201 SavingsAccount sa2(date, "02342342", 0.015); 202 CreditAccount ca(date, "C5392394", 10000, 0.0005, 50); 203 sa1.deposit(Date(2008, 11, 5), 5000, "Salary"); 204 ca.withdraw(Date(2008, 11, 15), 2000, "buy a cell"); 205 sa2.deposit(Date(2008, 11, 25), 10000, "sell stock 0323"); 206 ca.settle(Date(2008, 12, 1)); 207 ca.deposit(Date(2008, 12,1), 2016, "repay the credit"); 208 sa1.deposit(Date(2008, 12, 5), 5500, "salary"); 209 sa1.settle(Date(2009, 1, 1)); 210 sa2.settle(Date(2009, 1, 1)); 211 ca.settle(Date(2009, 1, 1)); 212 cout << endl; 213 sa1.show(); cout << endl; 214 sa2.show(); cout << endl; 215 ca.show(); cout << endl; 216 cout << "Total: " << Account::getTotal() << endl; 217 return 0; 218 219 }
截图：
问题：运用类的派生，提高代码复用性
