个人银行账户管理程序（C++）

最近在复习 C++ 基础知识，遇到了这个案例，这个案例涵盖了 C++ 很多重要的知识，如果有需要可以参考，代码和书中的一样。

程序分为 6 个文件：date.h 是日期类头文件，date.cpp 是日期类实现文件，accumulator.h 是为按日将数值累加的 Accumulator 类的头文件，account.h 是各个储蓄账户类定义头文件，account.cpp 是各个储蓄账户类实现文件，还有一个是主文件。代码如下：

//========================================== //Filename : 个人银行账户管理程序 //Time: 4月30日 //Authonr : 柚子树 //Email : gz_duyong@//==========================================#include <iostream>#include <fstream>#include <sstream>#include <string>#include <cmath>#include "account.h"#include <vector>#include <algorithm>using namespace std;struct deleter{template<class T>void operator()(T *p) {delete p; }};class Controller// 控制器，用来存储账户列表和处理命令{private:Date date;// 当前日期vector<Account*>accounts;// 账户列表bool end;// 用户是否输入了退出指令public:Controller(const Date &date) : date(date), end(false) {}~Controller();const Date &getDate() const {return date; }bool isEnd() const {return end; }// 执行一条命令，返回该命令是否改变了当前状态（即是否需要保存该命令）bool runCommand(const string &cmdLine);};Controller::~Controller(){for_each(accounts.begin(), accounts.end(), deleter());}bool Controller::runCommand(const string &cmdLine){istringstream str(cmdLine);char cmd, type;int index, day;double amount, credit, rate, fee;string id, desc;Account *account;Date date1, date2;str >> cmd;switch (cmd){case 'a':// 增加账户str >> type >> id;if (type == 's'){str >> rate;account = new SavingAccount(date, id, rate);}else{str >> credit >> rate >> fee;account = new CreditAccount(date, id, credit, rate, fee);}accounts.push_back(account);return true;case 'd':// 存入现金str >> index >> amount;getline(str, desc);accounts[index]->deposit(date, amount, desc);return true;case 'w':// 取出现金str >> index >> amount;getline(str, desc);accounts[index]->withdraw(date, amount, desc);return true;case 's':// 查询各账户信息for (size_t i = 0; i < accounts.size(); i++){cout << "[" << i << "]";accounts[i]->show(cout);cout << endl;}return false;case 'c':// 改变日期str >> day;if (day < date.getDay()){cout << "You cannot specify a previous day";}else if (day > date.getMaxDay()){cout << "Invalid day";}else{date = Date(date.getYear(), date.getMonth(), day);}return true;case 'n':// 进入下个月if (date.getMonth() == 12){date = Date(date.getYear() + 1, 1, 1);}else{date = Date(date.getYear(), date.getMonth() + 1, 1);}for (vector<Account*>::iterator iter = accounts.begin();iter != accounts.end(); ++iter){(*iter)->settle(date);}return true;case 'q':// 查询一段时间内的账目str >> date1 >> date2;Account::query(date1, date2);return false;case 'e':// 退出end = true;return false;}cout << "Invalid command: " << cmdLine << endl;return false;}int main(){Date date(, 11, 1);// 起始日期Controller controller(date);string cmdLine;const char *FILE_NAME = "command.txt";ifstream fileIn(FILE_NAME);// 以只读方式打开文件if (fileIn)// 如果正常打开，就执行文件中每一条指令{while (getline(fileIn, cmdLine)){try{controller.runCommand(cmdLine);}catch (const std::exception &e){cout << "Bad line in" << FILE_NAME << ": " << cmdLine << endl;cout << "Error: " << e.what() << endl;return 1;}}fileIn.close();// 关闭文件}ofstream fileOut(FILE_NAME, ios_base::app);// 以追加方式打开文件cout << "(a) add account (d) deposit (w) withdraw (s) show (c) change day (n) next month (q)query(e) exit" << endl;while (! controller.isEnd())// 从标准输入读入命令，直到退出{cout << controller.getDate() << "\tTotal: " << Account::getTotal() << "\tcommand>";string cmdLine;getline(cin, cmdLine);try{if (controller.runCommand(cmdLine)){fileOut << cmdLine << endl; // 将命令写入文件}}catch (AccountException &e){cout << "Error(#" << e.getAccount()->getId() << "): " << e.what() << endl;}catch (const std::exception &e){cout << "Error:" << e.what() << endl;}}system("pause");return EXIT_SUCCESS;}

// date.h#pragma once#ifndef __DATE_H__#define__DATE_H__#include <iostream>class Date// 日期类{public:Date(int year = 1, int month = 1, int day = 1);// 用年、月、日构造日期int getYear() const {return year; }int getMonth() const {return month; }int getDay() const {return day; }int getMaxDay() const;// 判断当月有多少天bool isLeapYear() const// 判断当年是否为闰年{return year % 4 == 0 && year % 100 != 0 || year % 400 == 0;}void show() const;// 输出当前日期// 计算两个日期之间差多少天int operator-(const Date &date) const{return totalDays - date.totalDays;}// 判断两个日期的前后顺序bool operator<(const Date &date) const{return totalDays < date.totalDays;}private:int year;int month;int day;int totalDays;// 该日期是从公元 1 月 1 日开始的第几天};std::istream &operator >> (std::istream &in, Date &date);std::ostream &operator << (std::ostream &out, const Date &date);#endif // !__DATE_H__

// date.cpp#include "date.h"#include <iostream>#include <stdexcept>#include <cstdlib>using namespace std;namespace{// namespace 使下面的定义只在当前文件中有效// 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const int DAYS_BEFORE_MONTH[] = {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304,334, 365 };}Date::Date(int year, int month, int day):year(year), month(month), day(day){if (day <= 0 || day > getMaxDay()) {throw runtime_error("Invalid date");}int years = year - 1;totalDays = years * 365 + years / 4 - years / 100 + years / 400+ DAYS_BEFORE_MONTH[month - 1] + day;if (isLeapYear() && month > 2){totalDays++;}}int Date::getMaxDay() const{if (isLeapYear() && month == 2){return 29;}else{return DAYS_BEFORE_MONTH[month] - DAYS_BEFORE_MONTH[month - 1];}}void Date::show() const{cout << getYear() << "-" << getMonth() << "-" << getDay();}std::istream & operator >> (std::istream & in, Date &date){int year, month, day;char c1, c2;in >> year >> c1 >> month >> c2 >> day;if (c1 != '-' || c2 != '-'){throw runtime_error("Bad time forman");}date = Date(year, month, day);return in;}std::ostream & operator<<(std::ostream & out, const Date &date){out << date.getYear() << "-" << date.getMonth() << "-" << date.getDay();return out;}

// accumulator.h#pragma once#ifndef __ACCUMULATOR_H__#define __ACCUMULATOR_H__#include "date.h"class Accumulator// 将某个数值按日累加{public:// 构造函数，date 为开始累加的日期，value 为初始值Accumulator(const Date &date, double value): lastDate(date), value(value), sum(0){}// 获得日期 date 的累加结果double getSum(const Date &date) const{return sum + value * (date - lastDate);}// 在 date 将数值变更为 valuevoid change(const Date &date, double value){sum = getSum(date);lastDate = date;this->value = value;}// 初始化，将日期变为 date，数值变为 value，累加器清零void reset(const Date &date, double value){lastDate = date;this->value = value;sum = 0;}private:Date lastDate;// 上次变更数值的日期double value;// 数值的当前值double sum;// 数值按日累加值};#endif // !__ACCUMULATOR_H__

// account.h#pragma once#include "date.h"#include "accumulator.h"#include <string>#include <map>#include <istream>#include <stdexcept>using namespace std;class Account;// 前置声明class AccountException : public std::runtime_error{private:const Account *account;public:AccountException(const Account *account, const std::string &msg):runtime_error(msg), account(account) {}const Account *getAccount() const {return account; }};class AccountRecord// 账目记录{private:Date date;// 日期const Account *account; // 账户double amount;// 金额double balance;// 余额string desc;// 描述public:// 构造函数AccountRecord(const Date &date, const Account *account, double amount, double balance, const string &desc);void show() const;// 输出当前记录};// 定义用来存储账目记录的多重映射类型typedef multimap<Date, AccountRecord>RecordMap;class Account// 账户类{private:string id;// 账号double balance;// 余额static double total;// 所有账户的总金额static RecordMap recordMap;// 账目记录protected:// 供派生类调用的构造函数，id 为账户Account(const Date &date, const string &id);// 记录一笔账，date 为日期， amount 为金额， desc 为说明void record(const Date &date, double amount, const string &desc);// 报告错误信息void error(const string &msg) const;public:const string &getId() const{return id;}double getBalancee() const{return balance;}static double getTotal(){return total;}// 存入现金，date 为日期，amount 为金额，desc 为款项说明virtual void deposit(const Date &date, double amount, const string &desc) = 0;// 取出现金，date 为日期，amount 为金额，desc 为款项说明virtual void withdraw(const Date &date, double amount, const string &desc) = 0;// 结算（计算利息、年费等），每月结算一次，date 为结算日期virtual void settle(const Date &date) = 0;// 显示账户信息virtual void show(std::ostream &out) const;//查询指定时间内的账目记录static void query(const Date &begin, const Date &end);};class SavingAccount : public Account// 储蓄账户类{private:Accumulator acc;// 辅助计算利息的累加器double rate;// 存款的年利率public:// 构造函数SavingAccount(const Date &date, const string &id, double rate);double getRate() const {return rate; }// 存入现金void deposit(const Date &date, double amount, const string &desc);// 取出现金void withdraw(const Date &date, double amount, const string &desc);void settle(const Date &date);// 结算利息，每年 1 月 1 日调用一次该函数};class CreditAccount : public Account// 信用账户类{private:Accumulator acc;// 辅助计算利息的累加器double credit;// 信用额度double rate;// 欠款的日利率double fee;// 信用卡年费double getDebt() const// 获得欠款额{double balance = getBalancee();return (balance < 0 ? balance : 0);}public:// 构造函数CreditAccount(const Date &date, const string &id, double credit, double rate, double fee);double getCredit() const {return credit; }double getRate() const {return rate; }double getFee() const {return fee; }double getAvailableCredit() const// 获得可用信用额度{if (getBalancee() < 0){return credit + getBalancee();}else{return credit;}}// 存入现金void deposit(const Date &date, double amount, const string &desc);// 取出现金void withdraw(const Date &date, double amount, const string &desc);void settle(const Date &date);void show(std::ostream &out) const;};inline std::ostream &operator<<(std::ostream &out, const Account &account){account.show(out);return out;}

// account.cpp#include "account.h"#include <cmath>#include <iostream>#include <utility>using namespace std;using namespace std::rel_ops;double Account::total = 0;//Account 类的实现RecordMap Account::recordMap;Account::Account(const Date & date, const string & id) : id(id), balance(0){cout << date << "\t#" << id << " created" << endl;}void Account::record(const Date & date, double amount, const string & desc){amount = floor(amount * 100 + 0.5) / 100;// 保留小数点后两位balance += amount;total += amount;date.show();cout << "\t#" << id << "\t" << amount << "\t" << balance << "\t" << desc << endl;}void Account::error(const string &msg) const{throw AccountException(this, msg);}void Account::show(ostream &out) const{cout << id << "\tBalance: " << balance;}void Account::query(const Date & begin, const Date & end){if (begin <= end){RecordMap::iterator iter1 = recordMap.lower_bound(begin);RecordMap::iterator iter2 = recordMap.upper_bound(end);for (RecordMap::iterator iter = iter1; iter != iter2; ++iter){iter->second.show();}}}// SavingAccount 类相关成员函数的实现SavingAccount::SavingAccount(const Date & date, const string & id, double rate): Account(date, id), rate(rate), acc(date, 0) {}void SavingAccount::deposit(const Date & date, double amount, const string & desc){record(date, amount, desc);acc.change(date, getBalancee());}void SavingAccount::withdraw(const Date & date, double amount, const string & desc){if (amount > getBalancee()){error("not enough money");}else{record(date, -amount, desc);acc.change(date, getBalancee());}}void SavingAccount::settle(const Date & date){if (date.getMonth() == 1){double interest = acc.getSum(date) * rate/ (date - Date(date.getYear() - 1, 1, 1));if (interest != 0){record(date, interest, "interest");}acc.reset(date, getBalancee());}}// CreditAccount 类相关成员函数的实现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) {}void CreditAccount::deposit(const Date & date, double amount, const string & desc){record(date, amount, desc);acc.change(date, getDebt());}void CreditAccount::withdraw(const Date & date, double amount, const string & desc){if (amount - getBalancee() > credit){error("not enough credit");}else{record(date, -amount, desc);acc.change(date, getDebt());}}void CreditAccount::settle(const Date & date){double interest = acc.getSum(date) * rate;if (interest != 0){record(date, interest, "interest");}if (date.getMonth() == 1){record(date, -fee, "annual fee");acc.reset(date, getDebt());}}void CreditAccount::show(ostream &out) const{Account::show(out);cout << "\tAvailable credit: " << getAvailableCredit();}// AccountRecord 类的实现AccountRecord::AccountRecord(const Date & date, const Account * account, double amount, double balance, const string & desc): date(date), account(account), balance(balance), desc(desc) {}void AccountRecord::show() const{cout << date << "\t#" << account->getId() << "\t" << amount << "\t" << balance << "\t" << desc << endl;}

运行结果：