我将如何创建LinkedList，然后根据输入创建值。 然后，如果输入与LinkedList中的值匹配，则返回该值？

Question

Below is my code, I want to create a Linkedlist, with input from a user. ONce the user has inputed values into the LinkedList(accounts). He can then search for those values in a LinkedList, if those values(account name) he inputed match those in the linkedList, then that value become the new account selected.

How can I finish my choose method.

import java.util.*;

public class Customer {

   public static void main(String[] args) {   
      new Customer();  
   }

   private LinkedList<Account> accounts = new LinkedList<Account>();

   public Customer() {
      setup();
   }

   private void setup() {
      accounts.add(new Account("",0.0));
      accounts.add(new Account("",0.0));
      accounts.add(new Account("",0.0));
   }

   public void use() {
      char choice;
      while((choice = readChoice()) != 'x') {
         switch(choice) {
            case 'a': choose(); break;
            case 'i': addInterest(); break;
            case 's': show(); break;
            default: help();
         }
      }   
   }

    private char readChoice() {   
       return 'x'; 
    }

    private void choose() {
        for (Account account: accounts) {
        }
    }

    private String readName() {
        System.out.print("??? account ???; ");
        return In.nextLine();
    }

    private Account account(String name) {  
       return null;    
    }

    private void addInterest() {  
       for (Account account: accounts) {  
          for (int i = 0; i < 30; i++)
              account.addDailyInterest();
          account.addMonthlyInterest();   
        }
     }

    private void help() {   
        String s = "The menu choices are";
        s += "\n  a: choose an account";
        s += "\n  i: add interest to all accounts";
        s += "\n  s show";
        s += "\n  x exit";
        System.out.println(s);   
    }

    private void show() {
        System.out.println(this);
    }

    public String toString() {   
        String s = "";
        return s;
    }
}

Answer 1

As I understand your problem logic, you want to be able to choose an account by name and set it as current. To do that you need to add a member to your Customer class that will store this selected Account , eg

Account selected; // null by default

Then the choose() method should loop through all accounts in order to find a match:

void choose(String name) {
   Account found = null;
   for (Account acc : accounts) {
      if (acc.getName().equals(name)) {
          found = acc;
      }
   }
   if (found) {
      selected = found;
   }
   else {
      System.out.println(name + " not found in list.");
}

As a suggestion, you can have show() that will display the account information from the selected (if it exists), and a showAll() that can display all accounts.

You need also to initialise properly the accounts list and write the logic in the main() .