第4章：类
class SavingsAccount { //储蓄账户类
private int id; //账号
private double balance; //余额
private double rate; //存款的年利率
private int lastDate; //上次变更余额的时期
private double accumulation; //余额按日累加之和
//记录一笔帐，date为日期，amount为金额，desc为说明
private void record(int date, double amount){
accumulation = accumulate(date);
lastDate = date;
amount = Math.floor(amount * 100 + 0.5) / 100; //保留小数点后两位
balance += amount;
System.out.println(date+"\t#"+id+"\t"+amount+"\t"+balance);
}
//获得到指定日期为止的存款金额按日累积值
private final double accumulate(int date) {
return accumulation + balance * (date - lastDate);
}
//构造函数
public SavingsAccount(int date, int id, double rate) {
this.id=id;
balance=0;
this.rate=rate;
lastDate=date;
accumulation=0;
System.out.println(date+"\t#"+id+" is created");
}
public int getId() {
return id;
}
public double getBalance() {
return balance;
}
public double getRate() {
return rate;
}
//存入现金
public void deposit(int date, double amount){
record(date, amount);
}
//取出现金
public void withdraw(int date, double amount){
if (amount > getBalance()) {
System.out.println("Error: not enough money");
}
else {
record(date, -amount);
}
}
//结算利息，每年1月1日调用一次该函数
public void settle(int date) {
double interest = accumulate(date) * rate / 365; //计算年息
if (interest != 0) {
record(date, interest);
}
accumulation = 0;
}
//显示账户信息
public void show(){
System.out.print("#"+id+"\tBalance: "+balance);
}
}
public class javafour {
public static void main(String[] args) {
//建立几个账户
SavingsAccount sa0 = new SavingsAccount(1,21325302,0.015);
SavingsAccount sa1 = new SavingsAccount(1, 58320212, 0.015);
//几笔账目
sa0.deposit(5, 5000);
sa1.deposit(25, 10000);
sa0.deposit(45, 5500);
sa1.withdraw(60, 4000);
//开户后第90天到了银行的计息日，结算所有账户的年息
sa0.settle(90);
sa1.settle(90);
//输出各个账户信息
sa0.show();
System.out.println();
sa1.show();
System.out.println();
}
}
第5章: 增添静态属性与方法
class SavingsAccount2{
private int id; //账号
private double balance; //余额
private double rate; //存款的年利率
private int 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;
//SavingsAccount类相关成员函数的实现
public SavingsAccount2(int date, int id, double rate){
this.id=id;
balance=0;
this.rate=rate;
lastDate=date;
accumulation=0;
System.out.println(date+"\t#"+id+" is created");
}
private void record(int date, double amount) {
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;
System.out.println(date+"\t#"+id+"\t"+amount+"\t"+balance);
}
private final double accumulate(int date) {
return accumulation + balance * (date - lastDate);
}
public int getId() {
return id;
}
public double getBalance() {
return balance;
}
public double getRate() {
return rate;
}
public void deposit(int date, double amount) {
record(date, amount);
}
public void withdraw(int date, double amount) {
if (amount > getBalance()) {
System.out.println("Error: not enough money");
}
else{
record(date, -amount);
}
}
public void settle(int date) {
double interest = accumulate(date) * rate / 365; //计算年息
if (interest != 0){
record(date, interest);
}
accumulation = 0;
}
public final void show() {
System.out.print("#"+id+"\tBalance: "+balance);
}
public static double getTotal(){
return total;
}
}
public class javafiveaccount{
public static void main(String[] args) {
//建立几个账户
SavingsAccount2 sa0 = new SavingsAccount2(1, 21325302, 0.015);
SavingsAccount2 sa1 = new SavingsAccount2(1, 58320212, 0.015);
//几笔账目
sa0.deposit(5, 5000);
sa1.deposit(25, 10000);
sa0.deposit(45, 5500);
sa1.withdraw(60, 4000);
//开户后第90天到了银行的计息日，结算所有账户的年息
sa0.settle(90);
sa1.settle(90);
//输出各个账户信息
sa0.show();
System.out.println();
sa1.show();
System.out.println();
System.out.print("Total: "+ SavingsAccount2.getTotal());
}
}
第6章：增添字符串、对象数组
class Date {
private int year;
private int month;
private int day;
private static int totalDays = 0;
public final int[] DAYS_BEFORE_MONTH= { 0,31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 };
public Date(int year, int month, int day){
this.year=year;
this.month=month;
this.day=day;
if (day <= 0 || day > getMaxDay()) {
System.out.print( "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++;
}
public final int getMaxDay(){
if (isLeapYear() && month == 2)
return 29;
else
return DAYS_BEFORE_MONTH[month] - DAYS_BEFORE_MONTH[month - 1];
}
public final void show() {
System.out.print(getYear()+"-"+getMonth()+"-"+ getDay());
}
public int getYear(){return year;}
public int getMonth(){return month;}
public int getDay(){return day;}
public final boolean isLeapYear(){
return year % 4 == 0 && year % 100 != 0 || year % 400 == 0;
}
public double distance(Date a){
return totalDays;
}
}
class SavingsAccount3{
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;
//SavingsAccount类相关成员函数的实现
public SavingsAccount3(final Date date, final String id, double rate) {
this.id=id;
balance=0;
this.rate=rate;
lastDate=date;
accumulation=0;
date.show();
System.out.println("\t#"+id+" is created");
}
public void record(final 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);
}
private final double accumulate(Date date) {
return accumulation + balance * (date.distance(date));
}
public String getId() {
return id;
}
public double getBalance() {
return balance;
}
public double getRate() {
return rate;
}
public final void error(final String msg){
System.out.println("Error(#" + id +"): " + msg );
}
public void deposit(final Date date, double amount, final String desc) {
record(date, amount, desc);
}
public void withdraw(final Date date, double amount, final String desc) {
if (amount > getBalance()) {
error("not enough money");
}
else {
record(date, -amount, desc);
}
}
public 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;
}
public final void show(){
System.out.print(id+"\tBalance: "+balance);
}
public static double getTotal(){
return total;
}
}
public class javasix{
public static void main(String[] args) {
Date date = new Date(2008, 11, 1); //起始日期
//建立几个账户
SavingsAccount3[] accounts= {
new SavingsAccount3(date, "S3755217", 0.015),
new SavingsAccount3(date, "02342342", 0.015)
};
final int n = accounts.length; /// size(SavingsAccount3); //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: "+ SavingsAccount3.getTotal());
}
}
第7章：继承与派生，抽象出父类，增添子类
class Date2{
private int year;
private int month;
private int day;
private static int totalDays = 0;
public final int[] DAYS_BEFORE_MONTH= { 0,31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 };
public Date2(int year, int month, int day){
this.year=year;
this.month=month;
this.day=day;
if (day <= 0 || day > getMaxDay()) {
System.out.print( "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++;
}
public final int getMaxDay(){
if (isLeapYear() && month == 2)
return 29;
else
return DAYS_BEFORE_MONTH[month] - DAYS_BEFORE_MONTH[month - 1];
}
public final void show() {
System.out.print(getYear()+"-"+getMonth()+"-"+ getDay());
}
public int getYear(){return year;}
public int getMonth(){return month;}
public int getDay(){return day;}
public final boolean isLeapYear(){
return year % 4 == 0 && year % 100 != 0 || year % 400 == 0;
}
public final int distance(final Date2 date){
return (totalDays -date.totalDays);
}
}
class Accumulator { //将某个数值按日累加
private Date2 lastDate; //上次变更数值的时期
private double value; //数值的当前值
private double sum; //数值按日累加之和
//构造函数，date为开始累加的日期，value为初始值
public Accumulator(final Date2 date, double value) {
lastDate=date;
this.value=value;
sum=0;
}
//获得到日期date的累加结果
public double getSum(final Date2 date) {
return sum + value * date.distance(lastDate);
}
//在date将数值变更为value
public void change(final Date2 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
public void reset(final Date2 date, double value) {
lastDate = date;
this.value = value;
sum = 0;
}
};
//Account类的实现
class Account {
private String id; //账号
private double balance; //余额
private static double total = 0;
public Account(final Date2 date, final String id) {
this.id = id;
balance = 0;
date.show();
System.out.println("\t#" + id + " created");
}
protected void record(final Date2 date, double amount, final String desc) {
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);
}
protected final void error(final String msg) {
System.out.println("Error(#" + id + "): " + msg);
}
public void show() {
System.out.print(id + "\tBalance: " + balance);
}
public final String getld(){return id;}
public double getBalance() {
return balance;
}
public static double getTotal() {
return total;
}
}
//SavingsAccount类相关成员函数的实现
class SavingsAccount4 extends Account{
private double rate;
private Accumulator acc;
public SavingsAccount4(final Date2 date,final String id,double rate) {
super(date, id);
//若一个父类只要有一个带参数的构造方法，
// 那么在写其子类的构造方法时必须先通过super调用父类的构造方法才能完成子类的构造方法而且super只能写在子类构造方法体内的第一行。
this.rate=rate;
acc=new Accumulator(date, 0);
}
public double getRate(){return rate;}
public void deposit(final Date2 date, double amount, final String desc) {
record(date, amount, desc);
acc.change(date, getBalance());
}
public void withdraw(final Date2 date, double amount, final String desc) {
if (amount > getBalance()) {
error("not enough money");
} else {
record(date, -amount, desc);
acc.change(date, getBalance());
}
}
public void settle(final Date2 date) {
double interest = acc.getSum(date) * rate //计算年息
/ date.distance(new Date2(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
class CreditAccount extends Account{
private double credit;
private double rate;
private double fee;
private Accumulator acc;
private final double getDebt(){
double balance = getBalance();
return (balance < 0 ? balance : 0);
}
public CreditAccount(final Date2 date,final String id, double credit, double rate, double fee) {
super(date, id);
this.credit=credit;
this.rate=rate;
this.fee=fee;
acc=new Accumulator(date, 0);
}
public final double getCredit() { return credit; }
public final double getRate() { return rate; }
public final double getFee() { return fee; }
public final double getAvailableCredit(){ //获得可用信用
if (getBalance() < 0)
return credit + getBalance();
else
return credit;
}
public void deposit(final Date2 date, double amount,final String desc) {
record(date, amount, desc);
acc.change(date, getDebt());
}
public void withdraw(final Date2 date, double amount,final String desc) {
if (amount - getBalance() > credit) {
error("not enough credit");
} else {
record(date, -amount, desc);
acc.change(date, getDebt());
}
}
public void settle(final Date2 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());
}
public final void show(){
super.show ();
System.out.print("\tAvailable credit:" + getAvailableCredit());
}
}
public class javaseven {
public static void main(String[] args) {
Date2 date= new Date2(2008, 11, 1); //起始日期
//建立几个账户
SavingsAccount4 sa1=new SavingsAccount4(date, "S3755217", 0.015);
SavingsAccount4 sa2=new SavingsAccount4(date, "02342342", 0.015);
CreditAccount ca=new CreditAccount(date, "C5392394", 10000, 0.0005, 50);
//11月份的几笔账目
sa1.deposit(new Date2(2008, 11, 5), 5000, "salary");
ca.withdraw(new Date2(2008, 11, 15), 2000, "buy a cell");
sa2.deposit(new Date2(2008, 11, 25), 10000, "sell stock 0323");
//结算信用卡
ca.settle(new Date2(2008, 12, 1));
//12月份的几笔账目
ca.deposit(new Date2(2008, 12, 1), 2016, "repay the credit");
sa1.deposit(new Date2(2008, 12, 5), 5500, "salary");
//结算所有账户
sa1.settle(new Date2(2009, 1, 1));
sa2.settle(new Date2(2009, 1, 1));
ca.settle(new Date2(2009, 1, 1));
//输出各个账户信息
System.out.println();
sa1.show();
System.out.println();
sa2.show();
System.out.println();
ca.show();
System.out.println();
System.out.println("Total: "+Account.getTotal());
}
}
第8章：多态特性
import java.util.Scanner;
class Date3{ //日期类
private int year; //年
private int month; //月
private int day; //日
private int totalDays; //该日期是从公元元年1月1日开始的第几天
public final int[] DAYS_BEFORE_MONTH= { 0,31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 };
public Date3(int year, int month, int day){//用年、月、日构造日期
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++;
}
public final int getYear() { return year; }
public final int getMonth() { return month; }
public final int getDay(){ return day; }
public final int getMaxDay(){//获得当月有多少天
if (isLeapYear() && month == 2)
return 29;
else
return DAYS_BEFORE_MONTH[month]- DAYS_BEFORE_MONTH[month - 1];
}
public final boolean isLeapYear() { //判断当年是否为闰年
return year % 4 == 0 && year % 100 != 0 || year % 400 == 0;
}
public final void show(){//输出当前日期
System.out.println( getYear() +"-" +getMonth()+ "-" +getDay());
}
//计算两个日期之间差多少天
public final int operator(final Date3 date){
return totalDays - date.totalDays;
}
}
class Accumulator2 { //将某个数值按日累加
private Date3 lastDate; //上次变更数值的时期
private double value; //数值的当前值
private double sum; //数值按日累加之和
//构造函数，date为开始累加的日期，value为初始值
public Accumulator2(final Date3 date, double value) {
lastDate=date;
this.value=value;
sum=0;
}
//获得到日期date的累加结果
public final double getSum(final Date3 date) {
return sum + value * (date.operator(lastDate));
}
//在date将数值变更为value
void change(final Date3 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(final Date3 date, double value) {
lastDate = date;
this.value = value;
sum = 0;
}
}
abstract class Account2 { //账户类
private String id; //帐号
private double balance; //余额
private static double total=0; //所有账户的总金额
//供派生类调用的构造函数，id为账户
protected Account2(final Date3 date, final String id){
this.id=id;
balance=0;
date.show();
System.out.println("\t#" +id + " created" );
}
//记录一笔帐，date为日期，amount为金额，desc为说明
protected void record(final Date3 date, double amount,final String desc){
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);
}
//报告错误信息
protected final void error(final String msg){
System.out.println("Error(#" + id + "): " + msg);
}
public final String getId() { return id; }
public final double getBalance(){ return balance; }
public static double getTotal() { return total; }
//存入现金，date为日期，amount为金额，desc为款项说明
public abstract void deposit(final Date3 date, double amount, final String desc);
//取出现金，date为日期，amount为金额，desc为款项说明
public abstract void withdraw(final Date3 date, double amount,final String desc);
//结算（计算利息、年费等），每月结算一次，date为结算日期
public abstract void settle(final Date3 date);
//显示账户信息
public void show(){
System.out.print(id + "\tBalance: " + balance);
}
};
class SavingsAccount5 extends Account2 { //储蓄账户类
private Accumulator2 acc; //辅助计算利息的累加器
private double rate; //存款的年利率
//构造函数
public SavingsAccount5(final Date3 date, final String id, double rate) {
super(date, id);
this.rate = rate;
acc = new Accumulator2(date, 0);
}
public final double getRate() {
return rate;
}
public void deposit(final Date3 date, double amount, final String desc) {
record(date, amount, desc);
acc.change(date, getBalance());
}
public void withdraw(final Date3 date, double amount, final String desc) {
if (amount > getBalance()) {
error("not enough money");
} else {
record(date, -amount, desc);
acc.change(date, getBalance());
}
}
public void settle(final Date3 date) {
if (date.getMonth() == 1) { //每年的一月计算一次利息
double interest = acc.getSum(date) * rate
/ (date.operator(new Date3(date.getYear() - 1, 1, 1)) );
if (interest != 0)
record(date, interest, "interest");
acc.reset(date, getBalance());
}
}
}
class CreditAccount2 extends Account2 { //信用账户类
private Accumulator2 acc; //辅助计算利息的累加器
private double credit; //信用额度
private double rate; //欠款的日利率
private double fee; //信用卡年费
private final double getDebt() { //获得欠款额
double balance = getBalance();
return (balance < 0 ? balance : 0);
}
//构造函数
public CreditAccount2(final Date3 date, final String id, double credit, double rate, double fee){
super(date,id);
this.credit=credit;
this.rate=rate;
this.fee=fee;
acc=new Accumulator2(date, 0);
}
public final double getCredit() { return credit; }
public final double getRate() { return rate; }
public final double getFee() { return fee; }
public final double getAvailableCredit() { //获得可用信用
if (getBalance() < 0)
return credit + getBalance();
else
return credit;
}
public void deposit(final Date3 date, double amount, final String desc){
record(date, amount, desc);
acc.change(date, getDebt());
}
public void withdraw(final Date3 date, double amount, final String desc){
if (amount - getBalance() > credit) {
error("not enough credit");
} else {
record(date, -amount, desc);
acc.change(date, getDebt());
}
}
public void settle(final Date3 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());
}
public void show(){
super.show();
System.out.print("\tAvailable credit:" + getAvailableCredit());
}
}
public class javaeight {
public static void main(String[] args) {
Date3 date=new Date3(2008, 11, 1); //起始日期
//建立几个账户
SavingsAccount5 sa1=new SavingsAccount5(date, "S3755217", 0.015);
SavingsAccount5 sa2=new SavingsAccount5(date, "02342342", 0.015);
CreditAccount2 ca=new CreditAccount2(date, "C5392394", 10000, 0.0005, 50);
Account2[] accounts={sa1, sa2, ca};
final int n; // sizeof(Account*); //账户总数
n = accounts.length;
System.out.println("(d)deposit (w)withdraw (s)show (c)change day (n)next month (e)exit" );
char cmd;
do {
//显示日期和总金额
date.show();
System.out.println("\tTotal: " +Account2.getTotal() + "\tcommand> ");
int index, day;
double amount;
String desc;
Scanner input=new Scanner(System.in);
String c=input.next();
cmd=c.charAt(0);
switch (cmd) {
case 'd': //存入现金
index=input.nextInt();
amount=input.nextDouble();
desc=input.next();
accounts[index].deposit(date, amount, desc);
break;
case 'w': //取出现金
index=input.nextInt();
amount=input.nextDouble();
desc=input.next();
accounts[index].withdraw(date, amount, desc);
break;
case 's': //查询各账户信息
for (int i = 0; i < n; i++) {
System.out.print("["+i+"] ");
accounts[i].show();
System.out.println();
}
break;
case 'c': //改变日期
day=input.nextInt();
if (day < date.getDay())
System.out.println("You cannot specify a previous day");
else if (day > date.getMaxDay())
System.out.println("Invalid day");
else
date = new Date3(date.getYear(), date.getMonth(), day);
break;
case 'n': //进入下个月
if (date.getMonth() == 12)
date = new Date3(date.getYear() + 1, 1, 1);
else
date = new Date3(date.getYear(), date.getMonth() + 1, 1);
for (int i = 0; i < n; i++)
accounts[i].settle(date);
break;
}
} while (cmd != 'e');
}
}
第9章：使用容器代替数组
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;
import java.util.*;
class Date4 { //日期类
private int year; //年
private int month; //月
private int day; //日
private int totalDays; //该日期是从公元元年1月1日开始的第几天
public final int[] DAYS_BEFORE_MONTH= { 0,31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 };
public Date4(int year, int month, int day){//用年、月、日构造日期
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++;
}
public final int getYear() { return year; }
public final int getMonth(){ return month; }
public final int getDay() { return day; }
public final int getMaxDay() {//获得当月有多少天
if (isLeapYear() && month == 2)
return 29;
else
return DAYS_BEFORE_MONTH[month]- DAYS_BEFORE_MONTH[month - 1];
}
public final boolean isLeapYear() { //判断当年是否为闰年
return year % 4 == 0 && year % 100 != 0 || year % 400 == 0;
}
public final void show() {//输出当前日期
System.out.println( getYear() +"-" +getMonth()+ "-" +getDay());
}
//计算两个日期之间差多少天
public final int operator(final Date4 date){
return totalDays - date.totalDays;
}
}
class Accumulator3 { //将某个数值按日累加
private Date4 lastDate; //上次变更数值的时期
private double value; //数值的当前值
private double sum; //数值按日累加之和
//构造函数，date为开始累加的日期，value为初始值
public Accumulator3(final Date4 date, double value) {
lastDate=date;
this.value=value;
sum=0;
}
//获得到日期date的累加结果
public final double getSum(final Date4 date) {
return sum + value * (date.operator(lastDate));
}
//在date将数值变更为value
void change(final Date4 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(final Date4 date, double value) {
lastDate = date;
this.value = value;
sum = 0;
}
}
abstract class Account3 { //账户类
private String id; //帐号
private double balance; //余额
private static double total; //所有账户的总金额
//供派生类调用的构造函数，id为账户
protected Account3(final Date4 date,final String id){
this.id=id;
balance=0;
date.show();
System.out.println("\t#" +id + " created" );
}
//记录一笔帐，date为日期，amount为金额，desc为说明
protected void record(final Date4 date, double amount,final String desc){
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);
}
//报告错误信息
protected final void error(final String msg){
System.out.println("Error(#" + id + "): " + msg);
}
public final String getId() { return id; }
public final double getBalance(){ return balance; }
public static double getTotal() { return total; }
//存入现金，date为日期，amount为金额，desc为款项说明
public abstract void deposit(final Date4 date, double amount,final String desc);
//取出现金，date为日期，amount为金额，desc为款项说明
public abstract void withdraw(final Date4 date, double amount,final String desc);
//结算（计算利息、年费等），每月结算一次，date为结算日期
public abstract void settle(final Date4 date);
//显示账户信息
public void show(){
System.out.print(id + "\tBalance: " + balance);
}
}
class SavingsAccount6 extends Account3 { //储蓄账户类
private Accumulator3 acc; //辅助计算利息的累加器
private double rate; //存款的年利率
//构造函数
public SavingsAccount6(final Date4 date,final String id, double rate){
super(date, id);
this.rate = rate;
acc = new Accumulator3(date, 0);
}
public final double getRate() { return rate; }
public void deposit(final Date4 date, double amount,final String desc){
record(date, amount, desc);
acc.change(date, getBalance());
}
public void withdraw(final Date4 date, double amount,final String desc){
if (amount > getBalance()) {
error("not enough money");
} else {
record(date, -amount, desc);
acc.change(date, getBalance());
}
}
public void settle(final Date4 date){
if (date.getMonth() == 1) { //每年的一月计算一次利息
double interest = acc.getSum(date) * rate
/ (date.operator(new Date4(date.getYear() - 1, 1, 1)) );
if (interest != 0)
record(date, interest, "interest");
acc.reset(date, getBalance());
}
}
}
class CreditAccount6 extends Account3 { //信用账户类
private Accumulator3 acc; //辅助计算利息的累加器
private double credit; //信用额度
private double rate; //欠款的日利率
private double fee; //信用卡年费
private final double getDebt(){ //获得欠款额
double balance = getBalance();
return (balance < 0 ? balance : 0);
}
//构造函数
public CreditAccount6(final Date4 date,final String id, double credit, double rate, double fee){
super(date,id);
this.credit=credit;
this.rate=rate;
this.fee=fee;
acc=new Accumulator3(date, 0);
}
public final double getCredit() { return credit; }
public final double getRate() { return rate; }
public final double getFee() { return fee; }
public final double getAvailableCredit(){ //获得可用信用
if (getBalance() < 0)
return credit + getBalance();
else
return credit;
}
public void deposit(final Date4 date, double amount,final String desc) {
record(date, amount, desc);
acc.change(date, getDebt());
}
public void withdraw(final Date4 date, double amount,final String desc){
if (amount - getBalance() > credit) {
error("not enough credit");
} else {
record(date, -amount, desc);
acc.change(date, getDebt());
}
}
public void settle(final Date4 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());
}
public void show(){
super.show();
System.out.print("\tAvailable credit:" + getAvailableCredit());
}
}
public class javanine {
public static void main(String[] args) {
Date4 date=new Date4(2008, 11, 1); //起始日期
//Array<Account *> accounts(0); 创建账户数组，元素个数为0
ArrayList<Account3> accounts = new ArrayList<>();
System.out.println("(a)add account (d)deposit (w)withdraw (s)show (c)change day (n)next month (e)exit" );
char cmd;
do {
//显示日期和总金额
date.show();
System.out.println("\tTotal: " +Account3.getTotal() + "\tcommand> ");
char type;
int index, day;
double amount, credit, rate, fee;
String id, desc;
Account3 account;
Scanner input=new Scanner(System.in);
String c=input.next();
cmd=c.charAt(0);
switch (cmd) {
case 'a': //增加账户
Scanner inputt=new Scanner(System.in);
String t=inputt.next();
type=t.charAt(0);
id=input.next();
if (type == 's') {
rate=input.nextDouble();
account = new SavingsAccount6(date, id, rate);
} else {
credit=input.nextDouble();
rate=input.nextDouble();
fee=input.nextDouble();
account = new CreditAccount6(date, id, credit, rate, fee);
}
//accounts.resize(accounts.length + 1);
accounts.add(account);
break;
case 'd': //存入现金
index=input.nextInt();
amount=input.nextDouble();
desc=input.next();
accounts.get(index).deposit(date, amount, desc);
break;
case 'w': //取出现金
index=input.nextInt();
amount=input.nextDouble();
desc=input.next();
accounts.get(index).withdraw(date, amount, desc);
break;
case 's': //查询各账户信息
for (int i = 0; i < accounts.size(); i++) {
System.out.print("["+i+"] ");
accounts.get(i).show();
System.out.println();
}
break;
case 'c': //改变日期
day=input.nextInt();
if (day < date.getDay())
System.out.println("You cannot specify a previous day");
else if (day > date.getMaxDay())
System.out.println("Invalid day");
else
date =new Date4(date.getYear(), date.getMonth(), day);
break;
case 'n': //进入下个月
if (date.getMonth() == 12)
date =new Date4(date.getYear() + 1, 1, 1);
else
date =new Date4(date.getYear(), date.getMonth() + 1, 1);
for (int i = 0; i < accounts.size(); i++)
accounts.get(i).settle(date);
break;
}
} while (cmd != 'e');
for (int i = 0; i < accounts.size(); i++)
accounts.remove(i);
}
}