Why am I getting all these exception errors?

Question about the task

Under discussion

I feel like I've solved the task as far as I can, but I'm not sure why I'm getting all these exception errors. I'm guessing it has something to do with either my loop never ending, or the fact that it can't handle parsing empty fields or something when it runs out of numbers. Any ideas?

Write a program that:
1. reads a number N (must be greater than 0) from the console
2. reads N numbers from the console
3. Displays the maximum of the N entered numbers.

Requirements:

The program should read the numbers from the keyboard.
The program must display a number on the screen.
The class must have a public static void main method.
Don't add new methods to the Solution class.
The program should display the maximum of the N entered numbers.
The program should not display anything if N is less than or equal to 0.

package com.codegym.task.task05.task0532; import java.io.*; /* Task about algorithms */ public class Solution { public static void main(String[] args) throws Exception { BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); int maximum = 0; int i = Integer.parseInt(reader.readLine()); if (i > maximum) { maximum = i; System.out.println(maximum); } else; while (true) { i = Integer.parseInt(reader.readLine()); if (maximum<i) maximum = i; else; if (i>0) System.out.println(maximum); else; } } }

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Gellert Varga

Level 23 , Szekesfehervar, Hungary

27 August 2021, 09:38

At the time I also had a hard time understanding what this task wanted from us... (Also because of language difficulties.) I like to express things much more clearly, I hope I can: 1) The first "N" entered determines how many numbers must follow. So, for example if the inputlist is something like this: 3, -67, -89, -12, then it means: we have to (read in and) check these 3 numbers: -67, -89, -12. In this case the correct output should be equal to -12 . 2) The sixth requiremet says: "The program should not display anything if N is less than or equal to 0." So, this first entered "N" can be even zero! Or negative, too. But to have zero elements or a negative number of elements is meaningless, therefore in this case the requirement is: "the program should not display anything." 3) You have set the maximum in line15 to 0, and -12 is not greater than zero yet it is the correct solution, so you will have to solve the check in a different way. 4) Yes, your program go into an almost infinite loop. For example if this is the input: 2 -1 -2 Then line 20 will print 2. Then it reads -1, line28 condition is not met, line32 condition is not met, next round comes: reads -2, now neither condition is met, next round: it reads the empty line, and is unable to convert it to int, so it throws an exception and stops.

Thomas

Level 41 , Bayreuth, Germany

27 August 2021, 06:59

If you do not need an else clause you can omit writing that keyword. Then you probably have missunderstood the task. It asks you to enter a positive number N. Now the second part of the task starts, enter N numbers (positive or negative) and find the maximum of these numbers. If a NumberForamtException occurs then this is pretty normal if you enter values other than ints.