Thread: Several questions about my code

Hello,

The comments in the code are my specified questions about the code. Please help me with finding the proper solution. I searched on the web, but I did not find the right solution for my problem. I couldn't find the right way to implement the information I found on the internet. So that's why I need some people who have more experience with Java who are willing to help me.

Could you help me please?

This is my code (with comments/questions):

 
import java.util.Scanner;
import java.util.ArrayList;
 
class Bank{
  double balance;
  //Account account;
  ArrayList<Account>account = new ArrayList<Account>();
  CommandReader commandReader;
 
  Bank(){
    commandReader = new CommandReader();
  }
 
  void run(){
    commandReader.run();  // The commandReader is a class which already should be fine
  }
 
  void enroll(String name){
    if(account.equals(account)){  //Why is this always true? I doesn't want to create two of the same accounts. In the commandReader the input is enroll Name
      System.out.println("already enrolled");
    } else {
      account.add(account); //This does also not work properly! when enroll Name is typed in by the user, there should be enrolled an account with name = Name and balance = 0
    }
  }
 
  void print(String name){
    if(account.equals(account)){
      System.out.println("Account of "+name);
      System.out.println("  balance: "+balance);
    } else {
      System.out.println("no such name "+name);
    }
  }
 
  void printAll(){
    if(account.equals(account)){
      System.out.println(account); //What I want to print here are all the accounts and they should be printed the same as the method above prints the accounts
    }
  }
 
  public static void main(String[] args){
      new Bank().run();
  }
}
 
class Account{
  double balance;
  String name;
 
  Account(){
    bank = new Bank(); //Is this necessary?
  }
 
  void user(String name, double balance){
    this.name = name;
    this.balance = balance;  //I think I don't understand it yet. The name and balance is what I want to store of the accounts
  }
}

I answered the questions in the code

 
import java.util.Scanner;
import java.util.ArrayList;
 
class Bank{
  double balance;
  //Account account;
  ArrayList<Account>account = new ArrayList<Account>();
  CommandReader commandReader;
 
  Bank(){
    commandReader = new CommandReader();
  }
 
  void run(){
    commandReader.run();  // The commandReader is a class which already should be fine
  }
 
  void enroll(String name){
    if(account.equals(account)){  //Why is this always true? I doesn't want to create two of the same accounts. In the commandReader the input is enroll Name\
//this is always true because you haven't defined a .equals in your Account Object so it is using the default equals method.  Which is never equal until you pass the same object in.
      System.out.println("already enrolled");
    } else {
      account.add(account); //This does also not work properly! when enroll Name is typed in by the user, there should be enrolled an account with name = Name and balance = 0
    }
  }
 
  void print(String name){
    if(account.equals(account)){
      System.out.println("Account of "+name);
      System.out.println("  balance: "+balance);
    } else {
      System.out.println("no such name "+name);
    }
  }
 
  void printAll(){
    if(account.equals(account)){
      System.out.println(account); //What I want to print here are all the accounts and they should be printed the same as the method above prints the accounts You need to define a toString //method in account to print the information out that you want. 
    }
  }
 
  public static void main(String[] args){
      new Bank().run();
  }
}
 
class Account{
  double balance;
  String name;
 
  Account(){
    bank = new Bank(); //Is this necessary?  I would probably pass a bank into the account class to associate the correct bank with the account.  Acount( Bank b){ bank= b;}
  }
 
  void user(String name, double balance){
    this.name = name;
    this.balance = balance;  //I think I don't understand it yet. The name and balance is what I want to store of the accounts
  }
}

I don't understand you. I'm a beginner in Java, so I'm not familiair with everything. How do I define the accounts.equals in my Account class? And do you know why my accound.add(account); doesn't work?

My whole code with some modifications:

import java.util.Scanner;
import java.util.ArrayList;
 
class Bank{
  double balance;
  //Account account;
  ArrayList<Account>account = new ArrayList<Account>();
  CommandReader commandReader;
 
  Bank(){
    commandReader = new CommandReader();
  }
 
  void run(){
    commandReader.run();
  }
 
  void enroll(String name){
    balance = 0;
    /*if(account.equals(account)){
      System.out.println("already enrolled");
    } else {*/
      account.add(user);
    //}
  }
 
  void deposit(String name, int amount){
    if(account.equals(account)){
      balance = balance + amount;
    } else {
      System.out.println("no such name "+name);
    }
  }
 
  void withdraw(String name, int amount){
    if(account.contains(name)){
      balance = balance - amount;
    } else {
      System.out.println("no such name "+name);
    }
  }
 
  void print(String name){
    if(account.equals(account)){
      System.out.println("Account of "+name);
      System.out.println("  balance: "+balance);
    } else {
      System.out.println("no such name "+name);
    }
  }
 
  void printAll(){
    /*if(account.contains()){
      System.out.println(account);
    }*/
    System.out.println(account.toString());
  }
 
  void printRed(){
    if (balance < 0){
      System.out.println(account.toString());
    } else {
      System.out.print("no negative balances");
    }
  }
 
  void interest (double rate){
 
  }
 
  public static void main(String[] args){
      new Bank().run();
  }
}
 
class CommandReader{
    Bank bank;
    Account account;
 
    /*
    CommandReader(Bank bank) {
        this.bank = bank;
    }*/
 
    /*CommandReader() {
        bank = new Bank();
    }*/
 
    // @pre: input complies to specified format
    void run(){
        Scanner scanner;
        String command;
        String name;
        int amount;
        scanner = new Scanner(System.in);
        bank = new Bank();
        do{
            command = scanner.next().toLowerCase();
            if (command.equals("enroll")) {
                name = scanner.next();
                bank.enroll(name);
            } else if (command.equals("deposit")) {
                name = scanner.next();
                amount = scanner.nextInt();
                bank.deposit(name, amount);
            } else if (command.equals("withdraw")) {
                name = scanner.next();
                amount = scanner.nextInt();
                bank.withdraw(name, amount);
            } else if (command.equals("print")) {
                name = scanner.next();
                bank.print(name);
            } else if (command.equals("printall")) {
                bank.printAll();
            } else if (command.equals("printred")) {
                bank.printRed();
            } else if (command.equals("interest")) {
                double rate = scanner.nextDouble();
                bank.interest(rate);
            } else if (command.equals("stop")) { 
                // do nothing
            } else {
                System.out.println("unknown command");
                // skip rest of line
                scanner.nextLine();
            }
        } while (! command.equals("stop"));
    }
}
 
class Account{
  String name;
  double balance;
 
  Account(Bank b){
    bank = b;
  }
 
  void user(String name, double balance){
    this.name = name;
    this.balance = balance;
  }
}

class Account{
  double balance;
  String name;
  Bank bank;
 
  Account(){ //default constructor
    this("", 0.0, null); 
   // bank = new Bank(); //Is this necessary?
  }
//fully specified constructor
  Account(String name, double balance, Bank b){
   this.name=name;
   this.balance=balance;
   this.bank= b;
  }
 
  void user(String name, double balance){
    this.name = name;
    this.balance = balance;
  }
 //I would normally define getters here and set all my variables to private.  If you do this You will need in isEquals to use a.getName().equals(name); instead of //a.name.equals(name);  this is an example of a getter
// public String getName(){
//return name;
// }
@Override // This is a string representation of your object
  public String toString(){
  return "Name: " + name+ " balance: " + balance;
}
@Override   // This is how you define an isEqual for this particular class.  Instead of it comparing if it is the same instance of a object it will compare the three things in the object.
 
public boolean equals(Account a){
 if(a.name.equals(name) && a.bank.equals(bank) && a.balance==balance){
 return true;
} 
 return false;
}
}

This is where I would start with your code for account

Thank you for your clear explanation! But I have still 1 question, how do I add a new account with a name which is entered by the user and an initial balance of 0? I want to do that in the enroll method in the class Bank.

This is what I have right now:

void enroll(String name){
   account.add(account);    //This should add new items to the ArrayList which should be stored stored in class Bank, for a clearer view: see the code I uploaded before
}