Question

我的教授给我的一项任务有点麻烦。这是提示：

修改Customer类以包含changeStreetO，changeCityO，changeStateO和changeZipO方法。 修改Account类以包含具有street，city，state和zip参数的changeAddressO方法。修改Bank应用程序以测试changeAddressO方法。

我有changeStreetO，changeCityO和changeStateO，以及changeZipO。但是，我对使用ChangeAddressO方法的粗体部分感到困惑。我想我理解如何编写参数，但我不确定实际方法中应该包含什么，以及它如何适应程序的其余部分。这是我目前的代码。

import java.text.NumberFormat;
import java.io.*;
import java.util.*;
public class BankModification
{
    public class Account 
    { 
        private double balance; 
        private Customer cust;

        public Account(double bal, String fName, String lName,  String str, String city, String st, String zip)
        {
            balance = bal;
            cust = new Customer(fName, lName, str, city, st, zip);
            /**
             * Returns the current balance
             * pre: none
             * post: The account balance has been returned
             */
        }

        public double getBalance()
        {
            return (balance);
        }

        /**
         * A deposit is made to the account
         * pre: none
         * post: The balance has been increased by the amount of the deposit.
         */
         public void deposit(double amt)
         {
            balance += amt;

            /**
             * A withdrawal is made from the account if there is enough money
             * pre: none
             * post: The balance has been decreased by the amount withdrawn.
             */
        }

        public void withdrawal(double amt)
        {
            if (amt <= balance) 
            balance -= amt;
            else 
            System. out. println ("Not enough money in account.");
        }


        /**
         * Returns a String that represents the Account object. 
         * pre: none
         * post: A string representing the Account object has been returned.
         */
        public String toString()
        {
            String accountString;
            NumberFormat money = NumberFormat.getCurrencyInstance();
            accountString = cust.toString();
            accountString += "Current balance is " + money.format (balance);
            return (accountString) ;
        }

        public changeAddressO(String street, String city, String state, zip_)
        {
        }

        public class Customer 
        {
            private String firstName, lastName, street, city,state, zip_;

            /**
             * constructor
             * pre: none
             * post: A Customer object has been created.
             * Customer data has been initialized with parameters
             */

            public Customer(String fName, String lName, String str,
        String c, String s, String z) 
            {
                firstName = fName;
                lastName = lName;
                street = str;
                city = c; 
                state = s; 
                zip_ = z;
            }

            /** 
             * Returns a String that represents the Customer Object 
             * pre: none
             * post: A string representing the Account object has been returned.
             */

            public String toString() 
            { 
                String custString;
                custString=firstName + " " + lastName + "\n";
                custString +=street + "\n";
                custString += city + ", "+state+ "  " + zip_ + "\n";
                return(custString);
            }

            public void ChangeStreetO(String newStreet)
            {
                street = newStreet;
            }

            public void ChangeCityO(String newCity)
            {
                city = newCity;
            }

            public void ChangeStateO(String newState)
            {
                state = newState;
            }

            public void ChangeZipO(String newZip)
            {
                zip_ = newZip;
            }
        }
    }
}

我不确定我是否遗漏了必要的东西，但如果没有changeAddressO方法，程序就会编译。因为我使用chageStreetO，changeCityO，changeStateO和changeZipO创建了方法，所以我无法弄清楚我需要在changeAddressO中放入什么。我对类和方法仍然有点困难。有人可以提供一些见解/指导来帮助解决这个问题吗？谢谢你的时间。

Answer 1

您只需要更改客户的地址：

    public void changeAddressO(String street, String city, String state, String zip)
            {
            cust.changeAddress(street);
            cust.changeCity(city);
            cust.changeState(state); 
            cust.changeZip(zip);
            }

Answer 2

    public void changeAddressO(String street, String city, String state, String zip_)
    {
        this.street = street;
        this.city = city;
        this. state = state;
        this.zip_ = zip_;

    }

您可能希望将它放在您的Customer类中，因为您将街道，城市，州和邮编设为私有。

Answer 3

首先，改变这个

public changeAddressO(String street, String city, String state, zip_)
{
}

到

public void changeAddressO(String street, String city, String state, String zip_)
{
}

所有函数都需要返回类型，并且所有参数在名称前都需要一个类型。此函数的返回类型为void，这意味着它不会向调用函数返回任何内容。根据需要将其更改为String或int或其他内容。

至少，现在你的代码将被编译。

此外，所有嵌套类都非常混乱。你希望教授不会这样给你。

首先改变这个：

public class BankModification
{
    public class Account
    {

      //Lots of stuff

        public class Customer
        {

            //Lots of stuff
        }
    }
}

到此（消除除第一个之外的所有public）：

public class BankModification
{
}
class Account
{
   //Lots of stuff
}
class Customer
{
   //Lots of stuff
}

这不会在功能上改变任何东西，但至少它不会让人感到困惑（注意BankModification中没有任何内容对此没什么帮助。）

“修改Bank应用程序以测试changeAddressO方法。”

什么银行申请？我希望看到一个

public static final void main(String[] as_cmdLineParams)

在那里的某个地方。这是在命令行上键入java BankModification时实际执行的函数（因为BankModification是公共类，只会执行其main。）

一些随机观察至少让你思考。

Java方法和类

3 个答案: