```
//9_16.cpp#include "account.h"#include "Array.h"#includeusing namespace std;int main() {Date date(2008, 11, 1);//起始日期Array accounts(0); //创建账户数组，元素个数为0
cout << "(a)add account (d)deposit (w)withdraw (s)show (c)change day (n)next month (e)exit" << endl;
char cmd;
do {
//显示日期和总金额
date.show();
cout << "\tTotal: " << Account::getTotal() << "\tcommand> ";
char type;
int index, day;
double amount, credit, rate, fee;
string id, desc;
Account* account;
cin >> cmd;
switch (cmd) {
case 'a': //增加账户
cin >> type >> id;
if (type == 's') {
cin >> rate;
account = new SavingsAccount(date, id, rate);
} else {
cin >> credit >> rate >> fee;
account = new CreditAccount(date, id, credit, rate, fee);
}
accounts.resize(accounts.getSize() + 1);
accounts[accounts.getSize() - 1] = account;
break;
case 'd': //存入现金
cin >> index >> amount;
getline(cin, desc);
accounts[index]->deposit(date, amount, desc);
break;
case 'w': //取出现金
cin >> index >> amount;
getline(cin, desc);
accounts[index]->withdraw(date, amount, desc);
break;
case 's': //查询各账户信息
for (int i = 0; i < accounts.getSize(); i++) {
cout << "[" << i << "] ";
accounts[i]->show();
cout << endl;
}
break;
case 'c': //改变日期
cin >> 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);
break;
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 (int i = 0; i < accounts.getSize(); i++)
accounts[i]->settle(date);
break;
}
} while (cmd != 'e');
for (int i = 0; i < accounts.getSize(); i++)
delete accounts[i];
return 0;
}
//account.cpp#include "account.h"#include#includeusing namespace std;
double Account::total = 0;
//Account类的实现
Account::Account(const Date &date, const string &id)
: id(id), balance(0) {
date.show();
cout << "\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::show() const {
cout << id << "\tBalance: " << balance;
}
void Account::error(const string &msg) const {
cout << "Error(#" << id << "): " << msg << endl;
}
//SavingsAccount类相关成员函数的实现
SavingsAccount::SavingsAccount(const Date &date, const string &id, double rate)
: Account(date, id), rate(rate), acc(date, 0) { }
void SavingsAccount::deposit(const Date &date, double amount, const string &desc) {
record(date, amount, desc);
acc.change(date, getBalance());
}
void SavingsAccount::withdraw(const Date &date, double amount, const string &desc) {
if (amount > getBalance()) {
error("not enough money");
} else {
record(date, -amount, desc);
acc.change(date, getBalance());
}
}
void SavingsAccount::settle(const Date &date) {
if (date.getMonth() == 1) { //每年的一月计算一次利息
double interest = acc.getSum(date) * rate
/ (date - Date(date.getYear() - 1, 1, 1));
if (interest != 0)
record(date, interest, "interest");
acc.reset(date, getBalance());
}
}
//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 - getBalance() > 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() const {
Account::show();
cout << "\tAvailable credit:" << getAvailableCredit();
}
//account.h#ifndef __ACCOUNT_H__#define __ACCOUNT_H__#include "date.h"#include "accumulator.h"#includeclass Account { //账户类
private:
std::string id; //帐号
double balance; //余额
static double total; //所有账户的总金额
protected:
//供派生类调用的构造函数，id为账户
Account(const Date &date, const std::string &id);
//记录一笔帐，date为日期，amount为金额，desc为说明
void record(const Date &date, double amount, const std::string &desc);
//报告错误信息
void error(const std::string &msg) const;
public:
const std::string &getId() const { return id; }
double getBalance() 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 std::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 std::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() const;
};
class SavingsAccount : 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
SavingsAccount(const Date &date, const std::string &id, double rate);
double getRate() const { return rate; }
virtual void deposit(const Date &date, double amount, const std::string &desc);
virtual void withdraw(const Date &date, double amount, const std::string &desc);
virtual void settle(const Date &date);
};
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 = getBalance();
return (balance < 0 ? balance : 0);
}
public:
//构造函数
CreditAccount(const Date &date, const std::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
if (getBalance() < 0)
return credit + getBalance();
else
return credit;
}
virtual void deposit(const Date &date, double amount, const std::string &desc);
virtual void withdraw(const Date &date, double amount, const std::string &desc);
virtual void settle(const Date &date);
virtual void show() const;
};
#endif //__ACCOUNT_H__
//accumulator.h
#ifndef __ACCUMULATOR_H__
#define __ACCUMULATOR_H__
#include "date.h"
class Accumulator { //将某个数值按日累加
private:
Date lastDate; //上次变更数值的时期
double value; //数值的当前值
double sum; //数值按日累加之和
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) { }
//获得到日期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value
void 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;
}
};
#endif //__ACCUMULATOR_H__
//Array.h#ifndef ARRAY_H#define ARRAY_H#include//数组类模板定义templateclass Array {private:T* list;//T类型指针，用于存放动态分配的数组内存首地址int size;//数组大小（元素个数）public:Array(int sz = 50);//构造函数Array(const Array&a);//拷贝构造函数~Array();//析构函数Array& operator = (const Array&rhs); //重载"="使数组对象可以整体赋值T & operator [] (int i);//重载"[]"，使Array对象可以起到C++普通数组的作用const T & operator [] (int i) const;//"[]"运算符的const版本operator T * ();//重载到T*类型的转换，使Array对象可以起到C++普通数组的作用operator const T * () const;//到T*类型转换操作符的const版本int getSize() const;//取数组的大小void resize(int sz);//修改数组的大小};//构造函数templateArray::Array(int sz) {assert(sz >= 0);//sz为数组大小（元素个数），应当非负size = sz;// 将元素个数赋值给变量sizelist = new T [size];//动态分配size个T类型的元素空间}//析构函数templateArray::~Array() {delete [] list;}//拷贝构造函数templateArray::Array(const Array&a) {//从对象x取得数组大小，并赋值给当前对象的成员size = a.size;//为对象申请内存并进行出错检查list = new T[size];// 动态分配n个T类型的元素空间//从对象X复制数组元素到本对象 for (int i = 0; i < size; i++)list[i] = a.list[i];}//重载"="运算符，将对象rhs赋值给本对象。实现对象之间的整体赋值templateArray&Array::operator = (const Array& rhs) {if (&rhs != this) {//如果本对象中数组大小与rhs不同，则删除数组原有内存，然后重新分配if (size != rhs.size) {delete [] list;//删除数组原有内存size = rhs.size;//设置本对象的数组大小list = new T[size];//重新分配n个元素的内存}//从对象X复制数组元素到本对象 for (int i = 0; i < size; i++)list[i] = rhs.list[i];}return *this;//返回当前对象的引用}//重载下标运算符，实现与普通数组一样通过下标访问元素，并且具有越界检查功能templateT &Array::operator[] (int n) {assert(n >= 0 && n < size);//检查下标是否越界return list[n];//返回下标为n的数组元素}templateconst T &Array::operator[] (int n) const {assert(n >= 0 && n < size);//检查下标是否越界return list[n];//返回下标为n的数组元素}//重载指针转换运算符，将Array类的对象名转换为T类型的指针，//指向当前对象中的私有数组。//因而可以象使用普通数组首地址一样使用Array类的对象名templateArray::operator T * () {return list;//返回当前对象中私有数组的首地址}templateArray::operator const T * () const {return list;//返回当前对象中私有数组的首地址}//取当前数组的大小templateint Array::getSize() const {return size;}// 将数组大小修改为sztemplatevoid Array::resize(int sz) {
assert(sz >= 0); //检查sz是否非负
if (sz == size) //如果指定的大小与原有大小一样，什么也不做
return;
T* newList = new T [sz]; //申请新的数组内存
int n = (sz < size) ? sz : size; //将sz与size中较小的一个赋值给n
//将原有数组中前n个元素复制到新数组中
for (int i = 0; i < n; i++)
newList[i] = list[i];
delete[] list; //删除原数组
list = newList; // 使list指向新数组
size = sz; //更新size
}
#endif //ARRAY_H
//date.cpp#include "date.h"#include#includeusing namespace std;
namespace { //namespace使下面的定义只在当前文件中有效
//存储平年中某个月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()) {
cout << "Invalid date: ";
show();
cout << endl;
exit(1);
}
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();
}
//date.h
#ifndef __DATE_H__
#define __DATE_H__
class Date { //日期类
private:
int year; //年
int month; //月
int day; //日
int totalDays; //该日期是从公元元年1月1日开始的第几天
public:
Date(int year, int month, int day); //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; //获得当月有多少天
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;
}
};
#endif //__DATE_H__
```