我正在为我的java类创建一个银行帐户程序，该程序可以管理多达5个不同的银行帐户。该程序必须允许创建一个新帐户，我已经完成，允许存款和取款，这也完成了，我无法工作的两个部分是1：银行最多只能有5个帐户，所以如果尝试创建第6个消息，显示已创建5个消息，2：其中一个选项必须打印出银行中当前帐户的所有帐户余额。
这是我现在的代码：
import java.util.Scanner;
public class Bankapp {
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
Bank myBank = new Bank();
int user_choice = 2;
do {
//display menu to user
//ask user for his choice and validate it (make sure it is between 1 and 6)
System.out.println();
System.out.println("1) Open a new bank account");
System.out.println("2) Deposit to a bank account");
System.out.println("3) Withdraw to bank account");
System.out.println("4) Print account balance");
System.out.println("5) Quit");
System.out.println();
System.out.print("Enter choice [1-5]: ");
user_choice = s.nextInt();
switch (user_choice) {
case 1:
System.out.println("Enter a customer name");
String cn = s.next();
System.out.println("Enter a opening balance");
double d = s.nextDouble();
System.out.println("Account was created and it has the following number: " + myBank.openNewAccount(cn, d));
break;
case 2: System.out.println("Enter a account number");
int an = s.nextInt();
System.out.println("Enter a deposit amount");
double da = s.nextDouble();
myBank.depositTo(an, da);
break;
case 3: System.out.println("Enter a account number");
int acn = s.nextInt();
System.out.println("Enter a withdraw amount");
double wa = s.nextDouble();
myBank.withdrawFrom(acn, wa);
break;
case 4: System.out.println("Enter a account number");
int anum = s.nextInt();
myBank.printAccountInfo(anum);
break;
case 5:
System.out.println("Here are the balances " + "for each account:");
case 6:
System.exit(0);
}
}
while (user_choice != '6');
}
static class Bank {
private BankAccount[] accounts; // all the bank accounts at this bank
private int numOfAccounts = 5; // the number of bank accounts at this bank
// Constructor: A new Bank object initially doesn’t contain any accounts.
public Bank() {
accounts = new BankAccount[5];
numOfAccounts = 0;
}
// Creates a new bank account using the customer name and the opening balance given as parameters
// and returns the account number of this new account. It also adds this account into the account list
// of the Bank calling object.
public int openNewAccount(String customerName, double openingBalance) {
BankAccount b = new BankAccount(customerName, openingBalance);
accounts[numOfAccounts] = b;
numOfAccounts++;
return b.getAccountNum();
}
// Withdraws the given amount from the account whose account number is given. If the account is
// not available at the bank, it should print a message.
public void withdrawFrom(int accountNum, double amount) {
for (int i =0; i<numOfAccounts; i++) {
if (accountNum == accounts[i].getAccountNum() ) {
accounts[i].withdraw(amount);
System.out.println("Amount withdrawn successfully");
return;
}
}
System.out.println("Account number not found.");
}
// Deposits the given amount to the account whose account number is given. If the account is not
// available at the bank, it should print a message.
public void depositTo(int accountNum, double amount) {
for (int i =0; i<numOfAccounts; i++) {
if (accountNum == accounts[i].getAccountNum() ) {
accounts[i].deposit(amount);
System.out.println("Amount deposited successfully");
return;
}
}
System.out.println("Account number not found.");
}
// Prints the account number, the customer name and the balance of the bank account whose
// account number is given. If the account is not available at the bank, it should print a message.
public void printAccountInfo(int accountNum) {
for (int i =0; i<numOfAccounts; i++) {
if (accountNum == accounts[i].getAccountNum() ) {
System.out.println(accounts[i].getAccountInfo());
return;
}
}
System.out.println("Account number not found.");
}
public void printAccountInfo(int accountNum, int n) {
for (int i =0; i<numOfAccounts; i++) {
if (accountNum == accounts[i].getAccountNum() ) {
System.out.println(accounts[i].getAccountInfo());
return;
}
}
System.out.println("Account number not found.");
}
}
static class BankAccount{
private int accountNum;
private String customerName;
private double balance;
private static int noOfAccounts=0;
public String getAccountInfo(){
return "Account number: " + accountNum + "\nCustomer Name: " + customerName + "\nBalance:" + balance +"\n";
}
public BankAccount(String abc, double xyz){
customerName = abc;
balance = xyz;
noOfAccounts ++;
accountNum = noOfAccounts;
}
public int getAccountNum(){
return accountNum;
}
public void deposit(double amount){
if (amount<=0) {
System.out.println("Amount to be deposited should be positive");
} else {
balance = balance + amount;
}
}
public void withdraw(double amount)
{
if (amount<=0){
System.out.println("Amount to be withdrawn should be positive");
}
else
{
if (balance < amount) {
System.out.println("Insufficient balance");
} else {
balance = balance - amount;
}
}
}
}//end of class
程序运行正常，我只需要添加这两个选项，并且无法使它们正常工作，我将如何进行此操作？此外，如果尚未创建任何帐户，则选项3和4不起作用。提前谢谢。
更新：这是我试过的，我一直得到一个这个方法必须返回类型int错误。
public int openNewAccount(String customerName, double openingBalance) {
if(numOfAccounts > 5)
{
System.out.println("5 accounts already exist");
}
else
{
BankAccount b = new BankAccount(customerName, openingBalance);
accounts[numOfAccounts] = b;
numOfAccounts++;
return b.getAccountNum();
}
}
更新2：我添加了一个退货声明，现在它运行时会打开最多为5的帐户，但是对于5号后的每个帐户，它只是说帐号是5而不是不开帐户。
public int openNewAccount(String customerName, double openingBalance) {
if(numOfAccounts > 5)
{
System.out.println("5 accounts already exist");
}
else
{
BankAccount b = new BankAccount(customerName, openingBalance);
accounts[numOfAccounts] = b;
numOfAccounts++;
return b.getAccountNum();
}
return numOfAccounts;
}
答案 0 :(得分：1)
非常简单。创建大小为5的列表，并在创建用户时将该帐户添加到该列表中。在添加之前，只需检查列表大小是否为＆lt; = 5.如果是，则继续添加帐户，否则抛出错误
对于选项2，只需遍历列表并显示结果
答案 1 :(得分：1)
1;在openNewBank帐户方法中;在创建新的银行帐户并将计数增加1之前;检查帐号是否已经达到5或更高，如果不是，请不要创建帐户，也不要增加帐号。
2：循环显示帐户变量并打印。
答案 2 :(得分：0)
我为它添加了密码系统。和漂亮的帐号 代码：
import java.io.*;
import java.util.Random;
public class Computer_Bank_of_India {
public static int NewRandom(int min, int max) {
Random rand = new Random();
int randomNum = rand.nextInt((max - min) + 1) + min;
return randomNum;
}
public static void main(String args[])throws IOException, InterruptedException {
InputStreamReader ir = new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(ir);
Bank myBank = new Bank();
int Option = 1, Account_Number, Account_Password, atempts = 0, Pass;
String Name;
double Balance, Money;
System.out.println("Please wait, the system is starting...");
while(Option !=5) {
Thread.sleep(4000);
System.out.println("1) Open a new bank account");
Thread.sleep(250);
System.out.println("2) Deposit to a bank account");
Thread.sleep(250);
System.out.println("3) Withdraw to bank account");
Thread.sleep(250);
System.out.println("4) Print the detailed account information including last transactions");
Thread.sleep(250);
System.out.println("5) Quit");
System.out.println();
System.out.print(" Enter Option [1-5]: ");
Option = Integer.parseInt(br.readLine());
switch(Option) {
case 1 : System.out.println("Enter a customer name :");
Name = br.readLine();
System.out.println("Enter a opening balance :");
Balance = Double.parseDouble(br.readLine());
Thread.sleep(250);
System.out.println("Creating your account....");
Thread.sleep(500);
int[] arrDetails= myBank.AddNewAccount(Name, Balance);
System.out.println("Account Has been created\n Account number: " + arrDetails[0]+"\nYour password : "+ arrDetails[1]);
break;
case 2 : System.out.println("Enter a account number :");
Account_Number = Integer.parseInt(br.readLine());
System.out.println("Enter a account password :");
Account_Password = Integer.parseInt(br.readLine());
System.out.println("Enter a deposit amount :");
Money = Double.parseDouble(br.readLine());
myBank.Deposit(Account_Number, Account_Password, Money);
break;
case 3 : System.out.println("Enter a account number :");
Account_Number = Integer.parseInt(br.readLine());
System.out.println("Enter a account password :");
Account_Password = Integer.parseInt(br.readLine());
System.out.println("Enter a deposit amount :");
Money = Double.parseDouble(br.readLine());
myBank.Withdraw(Account_Number, Account_Password, Money);
break;
case 4 : System.out.println("Enter a account number :");
Account_Number = Integer.parseInt(br.readLine());
System.out.println("Enter a account password :");
Account_Password = Integer.parseInt(br.readLine());
myBank.Transactions(Account_Number, Account_Password);
break;
case 5 : System.out.println("Please Enter your password :");
Pass = Integer.parseInt(br.readLine());
if(Pass == myBank.Password) {
System.out.println(" System shutting down.....");
Option = 5;
break;
}
else {
Thread.sleep(250);
System.out.println("You have enter a wrong password. Please try again");
Option = 0;
}
default: System.out.println("Invalid option. Please try again.");
}
}
}
static class Bank {
private int Password=2684;
private BankAccount[] accounts;
private int numOfAccounts;
public Bank() {
accounts = new BankAccount[100];
numOfAccounts = 0;
}
public int [] AddNewAccount(String Name, Double Balance) {
BankAccount b = new BankAccount(Name, Balance);
accounts[numOfAccounts] = b;
numOfAccounts++;
int Acc = b.getAccountNum()[0];
int Pass = b.getAccountNum()[1];
int[]details = {Acc, Pass};
return details;
}
public void Withdraw(int Account_Number, int pass, double Money) {
for (int i =0; i<numOfAccounts; i++) {
int a = accounts[i].getAccountNum()[0];
if (Account_Number == a) {
int p = accounts[i].getAccountNum()[1];
if( pass == p) {
accounts[i].withdraw(Money);
return;
}
}
}
System.out.println(" You have entered a wrong Account number or Password.");
}
public void Deposit(int Account_Number, int pass, double Money) {
for (int i =0; i<numOfAccounts; i++) {
int a = accounts[i].getAccountNum()[0];
if (Account_Number == a) {
int p = accounts[i].getAccountNum()[1];
if( pass == p) {
accounts[i].deposit(Money);
return;
}
}
}
System.out.println(" You have entered a wrong Account number or Password.");
}
public void Transactions(int Account_Number, int pass) {
for(int i = 0;i<numOfAccounts; i++) {
int a = accounts[i].getAccountNum()[0];
if (Account_Number == a ) {
int p = accounts[i].getAccountNum()[1];
if( pass == p) {
System.out.println(accounts[i].getAccountInfo());
System.out.println(" Last transaction: " + accounts[i].getTransactionInfo(accounts[i].getNumberOfTransactions()-1));
return;
}
}
}
System.out.println(" You have entered a wrong Account number or Password.");
}
}
static class BankAccount{
private int User_Password;
private int accountNum;
private String customerName;
private double balance;
private double[] transactions;
private String[] transactionsSummary;
private int numOfTransactions;
private static int noOfAccounts=0;
public String getAccountInfo(){
return " Account number: " + accountNum + "\n Customer Name: " + customerName + "\n Balance:" + balance +"\n";
}
public String getTransactionInfo(int n) {
String transaction = transactionsSummary[n];
return transaction;
}
public BankAccount(String abc, double xyz){
customerName = abc;
balance = xyz;
noOfAccounts ++;
User_Password = NewRandom(1000, 9999);
accountNum = NewRandom(800000000, 999999999);
transactions = new double[100];
transactionsSummary = new String[100];
transactions[0] = balance;
transactionsSummary[0] = "A balance of : Rs" + Double.toString(balance) + " was deposited.";
numOfTransactions = 1;
}
public int [] getAccountNum(){
int account = accountNum;
int Pass = User_Password;
int [] details = {account, Pass};
return details;
}
public int getNumberOfTransactions() {
return numOfTransactions;
}
public void deposit(double amount){
if (amount<=0) {
System.out.println("Amount to be deposited should be positive");
} else {
balance = balance + amount;
transactions[numOfTransactions] = amount;
transactionsSummary[numOfTransactions] = "Rs." + Double.toString(amount) + " was deposited.";
numOfTransactions++;
System.out.println(" Amount deposited successfully");
}
}
public void withdraw(double amount) {
if (amount<=0){
System.out.println("Amount to be withdrawn should be positive");
}
else {
if (balance < amount) {
System.out.println("Insufficient balance");
} else {
balance = balance - amount;
transactions[numOfTransactions] = amount;
transactionsSummary[numOfTransactions] = "Rs." + Double.toString(amount) + " was withdrawn.";
numOfTransactions++;
System.out.println(" Amount Withdrawn successfully");
}
}
}
}
}