Level 31

05.09.2018
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11comments

Need Help!

Question about the task

Under discussion

Output is correct however not passing verification

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.LinkedHashMap; 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)); LinkedHashMap<String, Integer> linkedHashMap = new LinkedHashMap<>(); int id ; String name; int flag = 0; for(int i = 0; flag != 1 ; i++) { id = Integer.parseInt(reader.readLine()); name = reader.readLine(); if(name.isEmpty()) flag = 1; if(flag == 1) { System.out.println("Id=" + id); linkedHashMap.put(name, id); } else { System.out.println("Id=" + id + " Name=" + name); linkedHashMap.put(name, id); } } for(Map.Entry<String, Integer> pair : linkedHashMap.entrySet()) { System.out.println(pair.getValue() + " " + pair.getKey()); } } }

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Ankush Rajput

Level 25 , Bhopal, India

8 September 2018, 11:05

Use a HashMap instead of LinkedHashMap as specified in question. Preserving order isn't required in ques, only key,value pair matching is need. Also, before (name.isEmpty()); reader will read the empty string, try to convert into int and will throw an exception and program will stop before checking for isEmpty function. Try to handle the exception.

Joyonta Saha

Level 31

7 September 2018, 13:44

However normal HashMap does not store data in insertion order

Pavlo Plynko Java Developer at CodeGym

7 September 2018, 07:25

In the main method, declare a HashMap variable and immediately initialize it. So, use exactly HashMap. Also, Integer.parseInt(reader.readLine()) gives exception for empty string.

Joyonta Saha

Level 31

6 September 2018, 11:07

Last verification analysis report

Joyonta Saha

Level 31

6 September 2018, 11:06

Joyonta Saha

Level 31

6 September 2018, 10:59

System.println.out() was used to display text as it had been listed in the condition. when flag = 1, helps to break the loop.

Joyonta Saha

Level 31

6 September 2018, 10:52

This portion actually checks whether the String is empty or not. (if flag = 1 then String is empty) If the String is empty(flag = 1) then we will add only the Integer data part into the Hashmap. else (flag = 0) we will add String and Integer pair into the Hashmap

Joyonta Saha

Level 31

6 September 2018, 10:49

if(name.isEmpty()) flag = 1; if(flag == 1) { System.out.println("Id=" + id); linkedHashMap.put(name, id); } else { System.out.println("Id=" + id + " Name=" + name); linkedHashMap.put(name, id); }

Joyonta Saha

Level 31

6 September 2018, 03:44

I used LinkedListHashMap because it stores data in the insertion order. 'flag' was used to check the next user input is empty or not. if empty then the from Integer-String pair only Integer i.e Value will be printed as per given condition. (Data should not be lost). what recommended by the mentor when I was no adding the last Integer-String pair (where String was empty ).

Roman

Level 41

6 September 2018, 05:51

Sorry, I want to ask What do you do in lines 30 and 35 ?

Roman

Level 41

5 September 2018, 14:05

What do you do in lines 31 and 36 ? In the if and else blocks (lines 28-37) you do the same operation

linkedHashMap.put(name, id);

why?