CodeGym/Help with Java Tasks/Output is correct but the task is not validated. Please h...

Level 41

09.11.2020
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Output is correct but the task is not validated. Please help!

Question about the task

Resolved

I have run the program with various combinations and it worked as expected. Even so, it won't validate.

public class Solution {

    static String family;
    static String city;
    static String cityByUser;

    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

        // List of addresses
        Map<String, String> addresses = new HashMap<>();
        while (true) {
            city = reader.readLine();
            family = reader.readLine();
            if (family.isEmpty() || city.isEmpty()) break;

            addresses.put(city, family);
        }

        // Read the city name
        cityByUser = reader.readLine();
        reader.close();

        Iterator <Map.Entry<String,String>> iterator = addresses.entrySet().iterator();
        while (iterator.hasNext())
        {
            Map.Entry<String, String> it1 = iterator.next();
            String family1 = it1.getValue();
            String city1 = it1.getKey();

            if (cityByUser.equals(city1)) System.out.println(family1);
            //else System.out.println("No family lives in this city");
        }
    }
}

package com.codegym.task.task08.task0829; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.util.*; /* Software update */ public class Solution { static String family; static String city; static String cityByUser; public static void main(String[] args) throws IOException { BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); // List of addresses Map<String, String> addresses = new HashMap<>(); while (true) { city = reader.readLine(); family = reader.readLine(); if (family.isEmpty() || city.isEmpty()) break; addresses.put(city, family); } // Read the city name cityByUser = reader.readLine(); reader.close(); Iterator <Map.Entry<String,String>> iterator = addresses.entrySet().iterator(); while (iterator.hasNext()) { Map.Entry<String, String> it1 = iterator.next(); String family1 = it1.getValue(); String city1 = it1.getKey(); if (cityByUser.equals(city1)) System.out.println(family1); //else System.out.println("No family lives in this city"); } } }

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Switch/Cypher

Level 25 , Bexleyheath, United Kingdom

9 November 2020, 16:50

Here:

if (family.isEmpty() || city.isEmpty()) break;

this condition will never happen.

Andrei

Level 41

9 November 2020, 17:18

What do you mean will never happen? :-/ If the user does not introduce either first row or second row by leaving the input space empty and pressing Enter it will happen, no?

Switch/Cypher

Level 25 , Bexleyheath, United Kingdom

9 November 2020, 18:59

My bad - you're right.

Guadalupe Gagnon

Level 37 , Tampa, United States

9 November 2020, 16:49

useful

As a programmer, unless you work for yourself, or you are the senior programmer in charge, you will have to structure your code to other fit the exact specifications and not your expectations. By not doing so your code will be unusable in larger programs and you will likely be fired or not paid. You need to treat these tasks as real life specifications. Follow them and you will pass; not following them by either accidently skipping an important step or getting creative and you will get errors in validation. Look at the example inputs. When I enter them this code does not do anything: "Chicago Capone New York City Rockefeller Seattle Gates Seattle" But it should output: Gates Also, don't use static variables where you don't have to. Lines 15-17, these variables are only temporary variables that are only used in the main method. There is no reason to have them in the Solution class.

Andrei

Level 41

9 November 2020, 17:21

Ugh.. I have tried multiple combinations like in the example input and it worked. I have reset the task and taken it from scratch, considering your advice.

Guadalupe Gagnon

Level 37 , Tampa, United States

9 November 2020, 17:35

solution

I would copy and paste this code. There is only one change to make to make this pass. hint: line 27 is incorrect.... the loop should only break when the family is blank Advise: Maps store values by a key, and the value can subsequently be retrieved by the key. You do not need to iterate over the map to find the key - value that matches the key when you can just just 'get' the value by passing in the key to the proper method. You could use this to replace lines 36-45 with only 1 line of code.

Andrei

Level 41

10 November 2020, 08:50

OK, here is my program, which passed the solution, with the same inputs as suggested. However, what is not clear to me is the following: 1. This first input asked is family name, but I put chicago. 2. Family is the key but I need to search by city, which is a value. Meaning after I introduce the cityByUser value I have the method containsKey(cityByUser).. but my string is a value, not a key. How is it looking for it?

public class Solution {

     public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
         String family;
         String city;
         String cityByUser;

        // List of addresses
        Map<String, String> addresses = new HashMap<>();
        while (true) {
            family = reader.readLine();
            if (family.isEmpty()) break;
            city = reader.readLine();

            addresses.put(family, city);
        }

        // Read the city name
        cityByUser = reader.readLine();
        reader.close();
        if (addresses.containsKey(cityByUser)) System.out.println(addresses.get(cityByUser));

    }
}

Guadalupe Gagnon

Level 37 , Tampa, United States

10 November 2020, 14:18

Variables can be named anything that you want them to be. Being that, you have misnamed the family and city in your while loop: You named the variable for the first input, which is for the city, "family" and put it in as the key and the other variable "city" (which is supposed to be family) which you put in the value. Your future coworkers and boss will complain if you continue doing this, however it makes no difference to the computer because it doesn't understand language as humans do. Disregarding the variable names completely, in the loop the task wants the first input to be the key and the second input to be value, which you did correctly. After the loop breaks you enter a last key to get the input from the map, which you did a batter job naming this variable "cityByUser". Disregarding its name, it is only used to get a value from the map by key.... which your program did successfully.

Andrei

Level 41

10 November 2020, 14:57

Yes, I realized that I am introducing city in the family variable, it was the only way I made it work at that moment, because I had switched the variables' names before (first city and second family) and it was not working; but maybe I also changed something else and did not realize it. Anyway, you are right regarding the work environment but I am confident that with time I will get better. I have already understood better this exercise with all the explaining! Thank you!

Guadalupe Gagnon

Level 37 , Tampa, United States

10 November 2020, 15:03

I have seen your code over last couple weeks and you are improving each time. Keep up the good work. Programming is one profession that you will never know everything in, you will be learning new things as long as you are in it. If you feel lost now just believe me when I say that we all felt the same exact way when we were first learning, I know I did. It just takes time, patience, and lots and lots of practice.

Andrei

Level 41

10 November 2020, 15:13

Thank you for the kind words! Yes, I often have moments currently when I feel lost but I just push on and continue reading and googling things and eventually they stick.. It's also a great exercise for patience, learning this skill !