Question

我正在尝试创建一个银行系统（面向对象），可以保存/存储用户必须输入的帐户信息。创建帐户后，可以使用帐号来找到/找到帐户，以便提取，存款，查看交易和删除。

我遇到的问题是交易部分。对于每个帐户，您必须能够按升序存储最后6个转移，并且必须打印。你能指导一下我应该寻找什么点。

class BankAccount{

private int accountNumber;
private String holderName;
private String holderAddress;
private String openDate;
private double balance;
private double[] transactions;
private String[] transactionsSummary;
private int numOfTransactions;
private  static int noOfAccounts=0;

public String getAccountInfo(){
    return "Account number: " + accountNumber + "\nCustomer Name: " + holderName + "\nHolder's Address: " + holderAddress + "\nOpen Date: " + openDate +  "\nBalance:" + balance +"\n";
}

public String getTransactionInfo(int n)
{
    String transaction = transactionsSummary[n];
    if (transaction == null) {
        return "No transaction exists with that number.";
    }
    else {
        return transaction;
    }
}

public BankAccount(String abc, double xyz, String address, String open){
    holderName = abc;
    balance = xyz;
    holderAddress = address;
    openDate = open;
    noOfAccounts ++;
    accountNumber = noOfAccounts;
    transactions = new double[100];
    transactionsSummary = new String[100];
    transactions[0] = balance;
    transactionsSummary[0] = "A balance of : $" + Double.toString(balance) + " was deposited.";
    numOfTransactions = 1;
}

public int getAccountNum(){
    return accountNumber;
}

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] = "$" + Double.toString(amount) + " was deposited.";
        numOfTransactions++;
    }
}

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        System.out.println("Amount to be withdrawn should be positive");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            transactionsSummary[numOfTransactions] = "$" + Double.toString(amount) + " was withdrawn.";
            numOfTransactions++;
        }
    }
}

}//end of class




class BankAccount{

private int accountNumber;
private String holderName;
private String holderAddress;
private String openDate;
private double balance;
private double[] transactions;
private String[] transactionsSummary;
private int numOfTransactions;
private  static int noOfAccounts=0;

public String getAccountInfo(){
    return "Account number: " + accountNumber + "\nCustomer Name: " + holderName + "\nHolder's Address: " + holderAddress + "\nOpen Date: " + openDate +  "\nBalance:" + balance +"\n";
}

public String getTransactionInfo(int n)
{
    String transaction = transactionsSummary[n];
    if (transaction == null) {
        return "No transaction exists with that number.";
    }
    else {
        return transaction;
    }
}

public BankAccount(String abc, double xyz, String address, String open){
    holderName = abc;
    balance = xyz;
    holderAddress = address;
    openDate = open;
    noOfAccounts ++;
    accountNumber = noOfAccounts;
    transactions = new double[100];
    transactionsSummary = new String[100];
    transactions[0] = balance;
    transactionsSummary[0] = "A balance of : $" + Double.toString(balance) + " was deposited.";
    numOfTransactions = 1;
}

public int getAccountNum(){
    return accountNumber;
}

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] = "$" + Double.toString(amount) + " was deposited.";
        numOfTransactions++;
    }
}

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] = "$" + Double.toString(amount) + " was withdrawn.";
            numOfTransactions++;
        }
    }
}

}//end of class

Answer 1

我只会给你一些提示。

首先，Java是一种OO语言，因此您应该使用对象。您应该拥有一个包含Transaction类型对象的数组，而不是拥有两个数组来保存事务数量和事务摘要。 Transaction类应包含字段amount和字段summary。

第二：您可以使用List<Transaction>而不是使用数组。每次有新的交易进入时，您都会在列表的末尾添加它。如果列表大小大于6，则删除列表的第一个元素（最旧的元素）。 LinkedList是此功能的不错选择。由于列表具有大小，因此您无需自己维护numOfTransactions。这个清单适合你。

您正在使用String来保存日期。这不是合适的类型。你应该使用日期。

您正在使用静态字段来保存已创建帐户的数量。那是糟糕的设计。您应该有一个Bank对象，其中包含银行的所有帐户（例如Map<Integer, BankAccount>，这样可以根据其编号查找帐户）。

Answer 2

如果您想使用数组执行此操作，则必须编写其他方法，并且应将事务和摘要放在一个类中（如@JB Nizet所说）。最好的方法是使用List。否则你必须自己编写所有方法。方法应如下所示：

import java.util.*;

private List<Transaction> transactions = new ArrayList<Transaction>();
public void addTransaction (Transaction t) {
    if (transactions.size() + 1 > 6)
        transactions.remove(0); // deletes the list element on the first place

    transactions.add(t);
}

如果你真的想要使用数组，打电话给我，我可以帮助你，但我建议你使用List。

我希望能帮到你！

Java - 银行系统+交易功能

2 个答案: