I think it's a verification issue?

Question about the task

User, loser, coder and programmer

Java Core, Level 4, Lesson 8

Resolved

Correct output - i think

1. Enter a few strings (keys) from the keyboard [in a loop].
The following strings (keys) are allowed: "user", "loser", "coder", "programmer".
Stop reading in strings after reading in any string that does not match one of the above.

2. For each entered string:
2.1. Create the appropriate object [see Person.java], e.g. create a User object for the string "user".
2.2. Pass this object to the doWork method.

3. Write an implementation of the doWork method, which:
3.1. Calls the live() method on the passed object if person is a User.
3.2. Calls the doNothing() method if person is a Loser.
3.3. Calls the writeCode() method if person is a Coder.
3.4. Calls the enjoy() method if person is a Programmer.

Requirements:

The main method must read strings from the keyboard.
The main method should stop reading strings from the keyboard as soon as the entered string does not match one of the allowed strings ("user", "loser", "coder", "programmer").
For each correctly entered string ("user", "loser", "coder", "programmer"), call the doWork method with the appropriate Person object as the argument.
The Solution class must implement a doWork method with one Person parameter.
The doWork method should call the live() method on the passed object if it is a User.
The doWork method should call the doNothing() method on the passed object if it is a Loser.
The doWork method should call the writeCode() method on the passed object if it is a Coder.
The doWork method should call the enjoy() method on the passed object if it is a Programmer.

package com.codegym.task.task14.task1411; import java.io.BufferedReader; import java.io.InputStreamReader; import java.util.Scanner; /* User, loser, coder and programmer */ public class Solution { public static void main(String[] args) throws Exception { BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); Person person = null; String key = null; boolean acceptInput = true; Scanner input = new Scanner(System.in); while (acceptInput) { key = input.next(); switch (key) { case "user": person = new Person.User(); break; case "loser": person = new Person.Loser(); break; case "coder": person = new Person.Coder(); break; case "programmer": person = new Person.Programmer(); break; default: System.exit(0); acceptInput = false; break; } doWork(person); } } public static void doWork(Person person) { // Item 3 if (person instanceof Person.Programmer) { ((Person.Programmer) person).enjoy(); } else if (person instanceof Person.Coder) { ((Person.Coder) person).writeCode(); } else if (person instanceof Person.Loser) { ((Person.Loser) person).doNothing(); } else if (person instanceof Person.User) { ((Person.User) person).live(); } } }

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slyyx

Level 15 , New York City, United States

4 November 2020, 02:08

solution

Found the issue myself: 1) user Switch/Cypher was correct about having

input.close();

instead of

System.exit(0);

2) the other issue was having line 40 where it was. If an incorrect input was entered, doWork(person); would print the last correct statement and then exit the loop. I fixed this by putting doWork(person) under each correct case (before the break statement)

case "user":
       person = new Person.User();
       doWork(person);
       break;
 case "loser":
        person = new Person.Loser();
        doWork(person);
        break;

etc.

Switch/Cypher

Level 25 , Bexleyheath, United Kingdom

3 November 2020, 11:17

useful

By "System.exit", I think you might mean:

input.close();

No? Also, why do you have a BufferedReader AND a Scanner? They are basically the same thing, and you declare the BufferedReader then don't use it.

Switch/Cypher

Level 25 , Bexleyheath, United Kingdom

3 November 2020, 11:21

And another thing, if the switch statement goes immediately to the default case (the first thing entered isn't any of the options), then I'm pretty sure you will get a 'Null Pointer Exception' thrown, because you are passing a 'null' object to 'doWork'. Just declare:

Person person;

it doesn't need to be "null" Same with String key. Declare it empty if you want:

String key = "";

but don't declare it "null". That's cruising for a bruising!

Nouser

Level 36 , Germany

3 November 2020, 06:40

worth a try would be to get rid of System.exit(0);