from allMoney.add()... ???🤷‍♂️

Question about the task

Currencies

Java Core, Level 4, Lesson 8

Resolved

Any hint, pls!? Tk you!

Expand the program's ability to manipulate currencies.

1. Create a private double field amount in the abstract Money class.
2. Create a public getter for the field amount (public double getAmount()) so you can access it outside the Money class.
3. In the separate files, create Euro, Ruble, and USD classes, which will be descendants of the Money class.
4. In the Euro, Ruble, and USD classes, implement the getCurrencyName method, which will return the abbreviated name of the currency (String) (EUR, RUB, USD).
5. In the Euro, Ruble, and USD classes, implement a public constructor that takes one argument and calls the constructor of the base class (super class) with this argument.
6. Populate the allMoney list with all possible currency objects in accordance with the task conditions and the functionality of the program.

Requirements:

The Money class must have a private double field amount.
The Money class must implement a public constructor with one double parameter, which sets the variable amount to the passed parameter.
The Money class must implement a public getAmount method that returns the value of the field amount.
The Euro, Ruble, and USD classes must be descendants of the Money class and be located in separate files.
The Euro, Ruble and USD classes must implement the getCurrencyName method.
The getCurrencyName method must return the abbreviated name of the corresponding currency (String).
The Euro, Ruble, and USD classes must implement a public constructor with one double parameter. This constructor must set the value of the Money class's field amount by calling the parent class's constructor with the same argument.

package com.codegym.task.task14.task1417; import java.util.ArrayList; import java.util.List; /* Currencies */ public class Solution { public static void main(String[] args) { Person paul = new Person("Paul"); for (Money money : paul.getAllMoney()) { System.out.println(paul.name + " has a stash of " + money.getAmount() + " " + money.getCurrencyName()); } } static class Person { public String name; Person(String name) { this.name = name; this.allMoney = new ArrayList<Money>(); //allMoney.add()...//<--this is not working, is not strange to .add() in ArrayList inside constructor??? } private List<Money> allMoney; public List<Money> getAllMoney() { return allMoney;} } }

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Guadalupe Gagnon

Level 37 , Tampa, United States

6 July 2020, 18:53

In the money class, the constructor is present but does not do anything. You may want to initialize the class field with the constructor. allMoney.add() works fine as long as you pass it an appropriate item. ArrayLists can only take in what they are declared. So if you had a String ArrayList, then you can add in String items or any class that extends Strings. If you had an Integer ArrayList then you could add in Integers or any class that extends Integer. Here the code has a Money ArrayList, therefore it should only take in ____________ or any class that extends ____________.

Angel Stefan Arjoca

Level 26 , Bucharest, Romania

7 July 2020, 10:49

In the end all i need to do is to initialize the amount variable inside the constructor in the Money class :) Tk you!