Output in wrong order

Question about the task

Functionality is not enough!

Java Syntax, Level 10, Lesson 11

Under discussion

The output of my solution has a wrong order: 2 I 1 Am 1 Sam How could i fix this. thank you

Task: The program reads a pair (a number and string) from the keyboard and displays it on the screen.
New task: The program reads pairs (a number and string) from the keyboard and stores them in a HashMap.
Any empty input signifies the end of data entry.
The numbers can be repeated.
The strings are always unique.
The entered data must not be lost!
The program then displays the contents of the HashMap on the screen.
Each pair on a new line.

Example input:
1 Sam 2 I 1 Am

Example output:
1 Sam 2 I 1 Am

Requirements:

The program must read data from the keyboard.
The program should display text on the screen.
In the main method, declare a HashMap variable and immediately initialize it.
The program should put the pairs read from the keyboard into the HashMap.
The program should display the contents of the HashMap in accordance with the conditions. The key and value are separated by a space. Each value should be on a new line.

package com.codegym.task.task10.task1019; import java.io.*; import java.util.HashMap; import java.util.Map; /* Functionality is not enough! */ public class Solution { public static void main(String[] args) throws IOException { BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); HashMap<String, Integer> map = new HashMap<>(); while (true) { String number = reader.readLine(); if (number.isEmpty()) break; Integer id = Integer.parseInt(number); String name = reader.readLine(); if (name.isEmpty()) break; map.put(name, id); } for (Map.Entry<String, Integer> mp : map.entrySet()) { System.out.println(mp.getValue() + " " + mp.getKey()); } } }

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Suhas Biwalkar

Level 11 , Nashua, United States

27 February 2020, 03:59

Everything is good. Just replace line 25 with this code. As per condition, if the number is entered and followed by a blank line, that number should be considered. if (name.isEmpty()){ map.put(name, id); break; }

Andrei

Level 26 , Liverpool, United Kingdom

25 February 2020, 01:07

had same problem, wrong order. I just added print method here: while (true) { String input = reader.readLine(); if (input == null) { break; } int number = Integer.parseInt(input); String name = reader.readLine(); if (name.isEmpty()) { System.out.println(number); map.put(name, number); }else{ System.out.println(number + " " + name); map.put(name, number); }

Guadalupe Gagnon

Level 37 , Tampa, United States

28 May 2019, 20:07

HashMaps (and Sets) make no promise of the order that will be pulled when iterating through them. The only way to pull them is an order that you want is by storing the keys and then sorting the keys in the way that you want the data pulled. This is not, however, the reason that verification is failing. I am thinking the task itself is worded incorrectly for what is being tested. I can't be sure but a lot of these tasks have to be 'tricked' into completing. 1) try using this for output: System.out.println("Id=" + id + " Name=" + name); It was in the starting code, maybe it will pass? 2) try testing for blank inputs with number/name.equals(""); 3) same as #2, but try .isBlank()

Pioniio

Level 22 , Schaffhausen, Switzerland

28 May 2019, 21:02

thanks, i tried wit sorting by Key with the follwing code: map.entrySet().stream().sorted(Map.Entry.comparingByKey()); map ist sorted now, but i need it in the reversed order,unfortunately i don't know how to update this to reverse.