C++代码源自《C++语言程序设计(第4版)》(清华大学计算机系列教材) 郑莉, 董渊, 何江舟 清华大学出版社
6_25
C++源码
//6_25.cpp
#include "account.cpp"
#include <iostream>
using namespace std;
int main() {
Date date(2008, 11, 1); //起始日期
//建立几个账户
SavingsAccount accounts[] = {
SavingsAccount(date, "S3755217", 0.015),
SavingsAccount(date, "02342342", 0.015)
};
const int n = sizeof(accounts) / sizeof(SavingsAccount); //账户总数
//11月份的几笔账目
accounts[0].deposit(Date(2008, 11, 5), 5000, "salary");
accounts[1].deposit(Date(2008, 11, 25), 10000, "sell stock 0323");
//12月份的几笔账目
accounts[0].deposit(Date(2008, 12, 5), 5500, "salary");
accounts[1].withdraw(Date(2008, 12, 20), 4000, "buy a laptop");
//结算所有账户并输出各个账户信息
cout << endl;
for (int i = 0; i < n; i++) {
accounts[i].settle(Date(2009, 1, 1));
accounts[i].show();
cout << endl;
}
cout << "Total: " << SavingsAccount::getTotal() << endl;
return 0;
}
//account.cpp
#include "account.h"
#include <cmath>
#include <iostream>
using namespace std;
double SavingsAccount::total = 0;
//SavingsAccount类相关成员函数的实现
SavingsAccount::SavingsAccount(const Date &date, const string &id, double rate)
: id(id), balance(0), rate(rate), lastDate(date), accumulation(0) {
date.show();
cout << "\t#" << id << " created" << endl;
}
void SavingsAccount::record(const Date &date, double amount, const string &desc) {
accumulation = accumulate(date);
lastDate = date;
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 SavingsAccount::error(const string &msg) const {
cout << "Error(#" << id << "): " << msg << endl;
}
void SavingsAccount::deposit(const Date &date, double amount, const string &desc) {
record(date, amount, desc);
}
void SavingsAccount::withdraw(const Date &date, double amount, const string &desc) {
if (amount > getBalance())
error("not enough money");
else
record(date, -amount, desc);
}
void SavingsAccount::settle(const Date &date) {
double interest = accumulate(date) * rate //计算年息
/ date.distance(Date(date.getYear() - 1, 1, 1));
if (interest != 0)
record(date, interest, "interest");
accumulation = 0;
}
void SavingsAccount::show() const {
cout << id << "\tBalance: " << balance;
}
//account.h
#ifndef __ACCOUNT_H__
#define __ACCOUNT_H__
#include "date.cpp"
#include <string>
class SavingsAccount { //储蓄账户类
private:
std::string id; //帐号
double balance; //余额
double rate; //存款的年利率
Date lastDate; //上次变更余额的时期
double accumulation; //余额按日累加之和
static double total; //所有账户的总金额
//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;
//获得到指定日期为止的存款金额按日累积值
double accumulate(const Date& date) const {
return accumulation + balance * date.distance(lastDate);
}
public:
//构造函数
SavingsAccount(const Date &date, const std::string &id, double rate);
const std::string &getId() const { return id; }
double getBalance() const { return balance; }
double getRate() const { return rate; }
static double getTotal() { return total; }
//存入现金
void deposit(const Date &date, double amount, const std::string &desc);
//取出现金
void withdraw(const Date &date, double amount, const std::string &desc);
//结算利息,每年1月1日调用一次该函数
void settle(const Date &date);
//显示账户信息
void show() const;
};
#endif //__ACCOUNT_H__
//date.cpp
#include "date.h"
#include <iostream>
#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 distance(const Date& date) const {
return totalDays - date.totalDays;
}
};
#endif //__DATE_H__
C++运行结果
Java代码
//Test.java
public class Test {
public static void main(String[] args) {
Date date=new Date(2008, 11, 1); //起始日期
//建立几个账户
SavingsAccount[] accounts = {
new SavingsAccount(date, "S3755217", 0.015),
new SavingsAccount(date, "02342342", 0.015)
};
final int n = accounts.length; //账户总数
//11月份的几笔账目
accounts[0].deposit(new Date(2008, 11, 5), 5000, "salary");
accounts[1].deposit(new Date(2008, 11, 25), 10000, "sell stock 0323");
//12月份的几笔账目
accounts[0].deposit(new Date(2008, 12, 5), 5500, "salary");
accounts[1].withdraw(new Date(2008, 12, 20), 4000, "buy a laptop");
//结算所有账户并输出各个账户信息
System.out.println();
for (int i = 0; i < n; i++) {
accounts[i].settle(new Date(2009, 1, 1));
accounts[i].show();
System.out.println();
}
System.out.println("Total: " + SavingsAccount.getTotal() +"\n");
}
}
//SavingsAccount.java
public class SavingsAccount {
private String id; // 账号
private double balance; // 余额
private double rate; // 存款的年利率
private Date lastDate; // 上次变更余额的时期
private double accumulation; // 余额按日累加之和
private static double total=0; // 所有账户的总金额
// 记录一笔帐,date为日期,amount为金额,desc为说明
private void record(Date date, double amount,final String desc) {
accumulation = accumulate(date);
lastDate = date;
amount = Math.floor((amount * 100 + 0.5) / 100);// 保留小数点后两位
balance += amount;
total += amount;
date.show();
System.out.println("\t#" + id + "\t" + amount + "\t" + balance + "\t" + desc);
}
// 获得到指定日期为止的存款金额按日累积值
private final double accumulate(Date date) {
return accumulation + balance * (date.distance(lastDate));
}
private final void error(final String msg) {
System.out.println("Error(#" + id + "): " + msg +"\n");
}
// 构造函数
SavingsAccount(final Date date, String id, double rate) {
this.id = id;
this.balance = 0;
this.rate = rate;
this.lastDate = date;
this.accumulation = 0;
date.show();
System.out.println("\t#" + id + "created");
}
final String getId() { return id; }
final double getBalance() { return balance;}
final double getRate() {return rate;}
static double getTotal() { return total;}
// 存入现金
void deposit(final Date date, double amount,final String desc) {
record(date, amount,desc);
}
// 取出现金
void withdraw(final Date date, double amount,final String desc) {
if (amount > getBalance())
error("not enough money\n");
else
record(date, -amount,desc);
}
// 结算利息,每年1月1日调用一次该函数
void settle(final Date date) {
double interest = accumulate(date) * rate //计算年息
/ date.distance(new Date(date.getYear() - 1, 1, 1));
if (interest != 0)
record(date, interest,"interest");
accumulation = 0;
}
// 显示账户信息
void show() {
System.out.println(id + "\tBalance: " + balance);
}
}
//Date.java
public class Date {
// 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
final int[] DAYS_BEFORE_MONTH = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 };
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) {
this.year = year;
this.month = month;
this.day = day;
if (day <= 0 || day > getMaxDay()) {
System.out.println("Invalid date: ");
show();
System.out.println();
System.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++;
}// 用年、月、日构造日期
final int getYear() {
return year;
}
final int getMonth() {
return month;
}
final int getDay() {
return day;
}
final int getMaxDay() {
if (isLeapYear() && month == 2)
return 29;
else
return DAYS_BEFORE_MONTH[month]- DAYS_BEFORE_MONTH[month - 1];
}; // 获得当月有多少天
final boolean isLeapYear() { //判断当年是否为闰年
return year % 4 == 0 && year % 100 != 0 || year % 400 == 0;
}
final void show() {
System.out.print( getYear()+ "-" + getMonth()+"-" + getDay());//输出当前日期
}
//计算两个日期之间差多少天
final int distance(final Date date) {
return totalDays - date.totalDays;
}
}