实验4 类的组合、继承、模板类、标准库
任务2
源码：
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 }
运行测试截图：
问题：
1.派生类GradeCalc定义中，成绩存储在vector<int>容器中；派生类方法sort, min, max, average,output通过vector<int>的成员函数begin(),end()访问到每个成绩；input方法通过vector<int>的成员函数push_back()接口实现数据存入对象
2.代码line68分母的功能是将成绩的总和除以人数获取平均分；去掉乘以1.0代码，重新编译、运行，结果将变为整数，精度下降；乘以1.0将平均分结果转换为小数，更加准确
3.程序没有对输入的数据进行合法性检验，无法处理异常输入数据；程序结果无法保留下来反复查看
任务3
源码：
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 }
运行测试截图：
问题：
1.组合类GradeCalc定义中，成绩存储内嵌对象vector<int> grades中；组合类方法sort, min, max, average,output通过vector<int>的成员函数begin(),end()访问到每个成绩；与实验任务2在代码写法上的差别主要为在类GradeCalc内通过定义的内嵌对象vector<int> grades来存储成绩，并对它进行求值等操作
2.当两个类存在一定关系，有时可以将它们设计为组合类，有时候可以将它们设计为派生类和基类，有时候两种设计方法都可以，但在类似于本次实验当中的任务中，派生类更加适用，因为使用派生类无需在设计派生类的过程中再创建内嵌对象，而是直接调用基类的成员函数
任务4
（1）
源码：
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 }
运行测试截图：
问题：
1.去掉line35后运行结果截图为
line35在这里的用途是清除输入缓存区中的剩余数据，确保下一次输入操作不会受到之前输入的影响（删除后会有空行产生）
(2)
源码：
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 }
运行测试截图：
（3）
源码：
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 }
运行测试截图：
问题：
1.去掉line16后运行结果截图为
line16在这里的用途是清除输入缓存区中的剩余数据，确保下一次输入操作不会受到之前输入的影响（删除后会有空字行产生）
任务5
源码：
1 #include <iostream> 2 using namespace std; 3 4 template<typename T> 5 6 class GameResourceManager { 7 public: 8 GameResourceManager(T resource0): resource{resource0} {} 9 ~GameResourceManager() {} 10 T get() const {return resource;} 11 void update(T resource0){ 12 if(resource0 > 0) 13 resource += resource0; 14 else 15 resource = max(resource + resource0, static_cast <T>(0)); 16 } 17 18 private: 19 T resource; 20 };
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 }
运行测试截图：
注：
将更新后的值与0比较时需要将0强制转换为模板类
任务6
源码：
1 #pragma once 2 3 #include <string> 4 #include <iostream> 5 #include <iomanip> 6 7 using namespace std; 8 9 class Info { 10 private: 11 string nickname; 12 string contact; 13 string city; 14 int n; 15 16 public: 17 Info(string nickname0, string contact0, string city0, int n0) 18 : nickname{nickname0}, contact{contact0}, city{city0}, n{n0} {} 19 20 void display() const { 21 cout << setw(10) << "昵称:" << nickname << endl 22 << setw(10) << "联系方式:" << contact << endl 23 << setw(10) << "所在城市：" << city << endl 24 << setw(10) << "预定参加人数: " << n << endl; 25 } 26 27 int get_n() const { 28 return n; 29 } 30 };
1 #include "info.hpp" 2 #include <iostream> 3 #include <vector> 4 #include <string> 5 #include <iomanip> 6 7 const int capacity = 100; 8 9 int main() { 10 vector<Info> audience_lst; 11 int current_capacity = 0; 12 13 string nickname, contact, city; 14 int n; 15 16 cout << "录入用户预约信息：" << endl << endl; 17 cout << left << setw(15) << "昵称" 18 << setw(30) << "联系方式（邮箱/手机号)" 19 << setw(15) << "所在城市" 20 << setw(15) << "预定参加人数 " << endl; 21 22 while (true) { 23 if (!(cin >> nickname)) break; //多组输入，按下Ctrl+Z时结束 24 cin >> contact; 25 cin >> city; 26 cin >> n; 27 28 if (current_capacity + n > capacity) { 29 cout << "对不起，只剩" << capacity - current_capacity << "个位置." << endl; 30 cout << "1.输入u，更新预定信息" << endl << "2.输入q，退出预定" << endl << "你的选择："; 31 char choice; 32 cin >> choice; 33 34 if (choice == 'q') { 35 break; 36 } 37 else if (choice == 'u') { 38 cout << "请重新输入预定信息：" << endl; 39 cin >> nickname >> contact >> city >> n; 40 } 41 else { 42 cout << "输入无效，请重新输入"; 43 continue; 44 } 45 } 46 47 Info audience(nickname, contact, city, n); 48 audience_lst.push_back(audience); 49 current_capacity += n; 50 51 if (current_capacity == capacity) 52 break; 53 } 54 55 cout << endl; 56 cout << "截至目前一共有" << current_capacity << "位听众预约。预约听众信息如下：" << endl; 57 for (const auto& info: audience_lst) { 58 info.display(); 59 cout << endl; 60 } 61 62 return 0; 63 }
运行测试截图：
注
setw()用于控制输出格式最小长度（iomanip头文件），left左对齐
任务7
源码：
1 //date.h 2 #ifndef __DATE_H__ 3 #define __DATE_H__ 4 class Date { //日期类 5 private: 6 int year; //年 7 int month; //月 8 int day; //日 9 int totalDays; //该日期是从公元元年1月1日开始的第几天 10 public: 11 Date(int year, int month, int day); //用年、月、日构造日期 12 int getYear() const { return year; } 13 int getMonth() const { return month; } 14 int getDay() const { return day; } 15 int getMaxDay() const; //获得当月有多少天 16 bool isLeapYear() const { //判断当年是否为闰年 17 return year % 4 == 0 && year % 100 != 0 || year % 400 == 0; 18 } 19 void show() const; //输出当前日期 20 //计算两个日期之间差多少天 21 int distance(const Date& date) const { 22 return totalDays - date.totalDays; 23 } 24 }; 25 #endif //__DATE_H__
1 //date.cpp 2 #include "date.h" 3 #include <iostream> 4 #include <cstdlib> 5 using namespace std; 6 namespace { //namespace使下面的定义只在当前文件中有效 7 //存储平年中的某个月1日之前有多少天，为便于getMaxDay函数的实现，该数组多出一项 8 const int DAYS_BEFORE_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 19 + DAYS_BEFORE_MONTH[month - 1] + day; 20 if (isLeapYear() && month > 2) totalDays++; 21 } 22 int Date::getMaxDay() const { 23 if (isLeapYear() && month == 2) 24 return 29; 25 else 26 return DAYS_BEFORE_MONTH[month]- DAYS_BEFORE_MONTH[month - 1]; 27 } 28 void Date::show() const { 29 cout << getYear() << "-" << getMonth() << "-" << getDay(); 30 }
1 //accumulator.h 2 #ifndef __ACCUMULATOR_H__ 3 #define __ACCUMULATOR_H__ 4 #include "date.h" 5 class Accumulator { //将某个数值按日累加 6 private: 7 Date lastDate; //上次变更数值的时期 8 double value; //数值的当前值 9 double sum; //数值按日累加之和 10 public: 11 //构造函数，date为开始累加的日期，value为初始值 12 Accumulator(const Date &date, double value) 13 : lastDate(date), value(value), sum(0) { } 14 //获得到日期date的累加结果 15 double getSum(const Date &date) const { 16 return sum + value * date.distance(lastDate); 17 } 18 //在date将数值变更为value 19 void change(const Date &date, double value) { 20 sum = getSum(date); 21 lastDate = date; this->value = value; 22 } 23 //初始化，将日期变为date，数值变为value，累加器清零 24 void reset(const Date &date, double value) { 25 lastDate = date; this->value = value; sum = 0; 26 } 27 }; 28 #endif //__ACCUMULATOR_H__
1 //account.h 2 #ifndef __ACCOUNT_H__ 3 #define __ACCOUNT_H__ 4 #include "date.h" 5 #include "accumulator.h" 6 #include <string> 7 class Account { //账户类 8 private: 9 std::string id; //帐号 10 double balance; //余额 11 static double total; //所有账户的总金额 12 protected: 13 //供派生类调用的构造函数，id为账户 14 Account(const Date &date, const std::string &id); 15 //记录一笔帐，date为日期，amount为金额，desc为说明 16 void record(const Date &date, double amount, const std::string &desc); 17 //报告错误信息 18 void error(const std::string &msg) const; 19 public: 20 const std::string &getId() const { return id; } 21 double getBalance() const { return balance; } 22 static double getTotal() { return total; } 23 //显示账户信息 24 void show() const; 25 }; 26 class SavingsAccount : public Account { //储蓄账户类 27 private: 28 Accumulator acc; //辅助计算利息的累加器 29 double rate; //存款的年利率 30 public: 31 //构造函数 32 SavingsAccount(const Date &date, const std::string &id, double rate); 33 double getRate() const { return rate; } 34 //存入现金 35 void deposit(const Date &date, double amount, const std::string &desc); 36 //取出现金 37 void withdraw(const Date &date, double amount, const std::string &desc); 38 void settle(const Date &date); //结算利息，每年1月1日调用一次该函数 39 }; 40 class CreditAccount : public Account { //信用账户类 41 private: 42 Accumulator acc; //辅助计算利息的累加器 43 double credit; //信用额度 44 double rate; //欠款的日利率 45 double fee; //信用卡年费 46 double getDebt() const { //获得欠款额 47 double balance = getBalance(); 48 return (balance < 0 ? balance : 0); 49 } 50 public: 51 //构造函数 52 CreditAccount(const Date &date, const std::string &id, double credit, double rate, double fee); 53 double getCredit() const { return credit; } 54 double getRate() const { return rate; } 55 double getFee() const { return fee; } 56 double getAvailableCredit() const { //获得可用信用 57 if (getBalance() < 0) 58 return credit + getBalance(); 59 else 60 return credit; 61 } 62 //存入现金 63 void deposit(const Date &date, double amount, const std::string &desc); 64 //取出现金 65 void withdraw(const Date &date, double amount, const std::string &desc); 66 void settle(const Date &date); //结算利息和年费，每月1日调用一次该函数 67 void show() const; 68 }; 69 #endif //__ACCOUNT_H__
1 //account.cpp 2 #include "account.h" 3 #include <cmath> 4 #include <iostream> 5 using namespace std; 6 double Account::total = 0; 7 //Account类的实现 8 Account::Account(const Date &date, const string &id) 9 : id(id), balance(0) { 10 date.show(); cout << "\t#" << id << " created" << endl; 11 } 12 void Account::record(const Date &date, double amount, const string &desc) { 13 amount = floor(amount * 100 + 0.5) / 100; //保留小数点后两位 14 balance += amount; total += amount; 15 date.show(); 16 cout << "\t#" << id << "\t" << amount << "\t" << balance << "\t" << desc << endl; 17 } 18 void Account::show() const { cout << id << "\tBalance: " << balance; } 19 void Account::error(const string &msg) const { 20 cout << "Error(#" << id << "): " << msg << endl; 21 } 22 //SavingsAccount类相关成员函数的实现 23 SavingsAccount::SavingsAccount(const Date &date, const string &id, double rate) 24 : Account(date, id), rate(rate), acc(date, 0) { } 25 void SavingsAccount::deposit(const Date &date, double amount, const string &desc) { 26 record(date, amount, desc); 27 acc.change(date, getBalance()); 28 } 29 void SavingsAccount::withdraw(const Date &date, double amount, const string &desc) { 30 if (amount > getBalance()) { 31 error("not enough money"); 32 } else { 33 record(date, -amount, desc); 34 acc.change(date, getBalance()); 35 } 36 } 37 void SavingsAccount::settle(const Date &date) { 38 double interest = acc.getSum(date) * rate //计算年息 39 / date.distance(Date(date.getYear() - 1, 1, 1)); 40 if (interest != 0) record(date, interest, "interest"); 41 acc.reset(date, getBalance()); 42 } 43 //CreditAccount类相关成员函数的实现 44 CreditAccount::CreditAccount(const Date& date, const string& id, double credit, double rate, double fee) 45 : Account(date, id), credit(credit), rate(rate), fee(fee), acc(date, 0) { } 46 void CreditAccount::deposit(const Date &date, double amount, const string &desc) { 47 record(date, amount, desc); 48 acc.change(date, getDebt()); 49 } 50 void CreditAccount::withdraw(const Date &date, double amount, const string &desc) { 51 if (amount - getBalance() > credit) { 52 error("not enough credit"); 53 } else { 54 record(date, -amount, desc); 55 acc.change(date, getDebt()); 56 } 57 } 58 void CreditAccount::settle(const Date &date) { 59 double interest = acc.getSum(date) * rate; 60 if (interest != 0) record(date, interest, "interest"); 61 if (date.getMonth() == 1) 62 record(date, -fee, "annual fee"); 63 acc.reset(date, getDebt()); 64 } 65 void CreditAccount::show() const { 66 Account::show(); 67 cout << "\tAvailable credit:" << getAvailableCredit(); 68 }
1 //7_10.cpp 2 #include "account.h" 3 #include <iostream> 4 using namespace std; 5 int main() { 6 Date date(2008, 11, 1); //起始日期 7 //建立几个账户 8 SavingsAccount sa1(date, "S3755217", 0.015); 9 SavingsAccount sa2(date, "02342342", 0.015); 10 CreditAccount ca(date, "C5392394", 10000, 0.0005, 50); 11 //11月份的几笔账目 12 sa1.deposit(Date(2008, 11, 5), 5000, "salary"); 13 ca.withdraw(Date(2008, 11, 15), 2000, "buy a cell"); 14 sa2.deposit(Date(2008, 11, 25), 10000, "sell stock 0323"); 15 //结算信用卡 16 ca.settle(Date(2008, 12, 1)); 17 //12月份的几笔账目 18 ca.deposit(Date(2008, 12, 1), 2016, "repay the credit"); 19 sa1.deposit(Date(2008, 12, 5), 5500, "salary"); 20 //结算所有账户 21 sa1.settle(Date(2009, 1, 1)); 22 sa2.settle(Date(2009, 1, 1)); 23 ca.settle(Date(2009, 1, 1)); 24 //输出各个账户信息 25 cout << endl; 26 sa1.show(); cout << endl; 27 sa2.show(); cout << endl; 28 ca.show(); cout << endl; 29 cout << "Total: " << Account::getTotal() << endl; 30 return 0; 31 }
运行测试截图：
问题：
1.增加了储蓄账户类的派生类信用账户类（公有继承），完善了银行储蓄账户的种类，更加符合生活实际
2.不同派生类的函数相互独立，只有知道对象的具体类型后才能调用
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