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Thread: nextInt - can not find InputMismatchException

  1. #1
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    Default nextInt - can not find InputMismatchException

    I am trying to read three integers from user.However,as always,i have to check if the input is ok.So i wrote the code,but can not find a way to ensure that the input is ok.InputMismatchException seems to suit but when i write her i get the error : Uncompilable source code - cannot find symbol

    Here is my code.What am i missing? :/

    static void getInput(int[] input) {
            System.out.print("Please enter length of phrase,minimum number of words"
                    + " of the essay and maximum number of words : ");
     
            try{
                Scanner in = new Scanner(System.in);
                for(int i=0 ; i<input.length ; i++)
                    input[i] = in.nextInt();
            } catch (InputMismatchException e) {
                System.err.println("Unexpected IO ERROR: " + e.toString());
            }
     
        }

    PS1- yes you guess it right i am a newbie,so every tip is a treasure for me
    PS2 - how can i wrap my code to something that colours the functions etc.


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: nextInt - can not find InputMismatchException

    You didn't post the import statements for your code so we can't see what you are using.

    To find what package a class is in, look it up in the API doc:
    Java Platform SE 7

    At the top of the page for the class will be its definition showing what package it is in.
    For example InputStream has this at the top:
    java.io.InputStream
    showing that InputStream is in the java.io package. You would use that in the import statement.
    If you don't understand my answer, don't ignore it, ask a question.

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    Super Moderator helloworld922's Avatar
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    Default Re: nextInt - can not find InputMismatchException

    To have the forum highlight/color your code, specify a language. For example:

    [code=java]//your code goes here[/code]

    This looks like:
    //your code goes here

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    Default Re: nextInt - can not find InputMismatchException

    Here is the whole code
    package essaycorrection;
     
    import java.util.Scanner;
     
    public class EssayCorrection {
     
        public static void main(String[] args) {
            int[] input = new int[3];//N,minWords,maxWords
            getInput(input);
            Phrase test = new Phrase(input[0]);
     
        }
     
        static void getInput(int[] input) {
            System.out.print("Please enter length of phrase,minimum number of words"
                    + " of the essay and maximum number of words : ");
     
           // try{
                Scanner in = new Scanner(System.in);
                for(int i=0 ; i<input.length ; i++)
                    input[i] = in.nextInt();
    //        } catch (InputMismatchException e) {
    //            System.err.println("Unexpected IO ERROR: " + e.toString());
    //        }
     
        }
    }
    Still can not find it,even after looking at the link :/

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    Super Moderator helloworld922's Avatar
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    Default Re: nextInt - can not find InputMismatchException

    Here's the Javadoc for InputMistmatchException

    Pretty much the first line tells you which package this class is in. This is right above the class name and inheritance hierarchy. You need to import the class before you can use it.

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    Default Re: nextInt - can not find InputMismatchException

    Duplicate link,but you did good to repost in order to emphasize the importance of it So what was missing was this line
    [code=java]import java.util.InputMismatchException;[code]
    So now i got it together,and my goal is that when the user inputs some letters instead of numbers then the user will be able to input again and so on.
    static void getInput(int[] input) {
            boolean error = false;
            System.out.print("Please enter length of phrase,minimum number of words"
                    + " of the essay and maximum number of words : ");
            do {
                try {
                    Scanner in = new Scanner(System.in);
                    for (int i = 0; i < input.length; i++) {
                        input[i] = in.nextInt();
                    }
                } catch (InputMismatchException e) {
                    System.err.println("Unexpected IO ERROR: " + e.toString());
                    error = true;
                }
            } while (error);
     
        }

    So i typed "dd" ,exception was thrown as it was expected but then nothing happens.What i am missing again? :/

  7. #7
    Super Moderator Norm's Avatar
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    Default Re: nextInt - can not find InputMismatchException

    exception was thrown as it was expected but then nothing happens
    Please explain. What do you expect to happen?

    Please post the contents of the console from your test.
    To copy the contents of the command prompt window:
    Click on Icon in upper left corner
    Select Edit
    Select 'Select All' - The selection will show
    Click in upper left again
    Select Edit and click 'Copy'

    Paste here.
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: nextInt - can not find InputMismatchException

    Can't find the icon but i copy pasted the output.(from netbeans)
    run:
    Please enter length of phrase,minimum number of words of the essay and maximum number of words : dd
    Unexpected IO ERROR: java.util.InputMismatchException
    5 5 5
    BUILD STOPPED (total time: 11 seconds)
    What i expect to happen is this : as long as the input is not ok,i want to get the user input again.So when the exception is thrown this means something is not ok so re-input!

    Idea->Does the exception makes the stream to close?That is what is happening?

  9. #9
    Super Moderator Norm's Avatar
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    Default Re: nextInt - can not find InputMismatchException

    Does the exception makes the stream to close?That is what is happening?
    Why do you think that? What happened to the input: 5 5 5? Did the program read that OK?

    Try debugging the code by printing out each number after it is read. Be sure to include an ID String with the printout:
    S.o.println("read: " + input[i] + ", i=" +i);

    Also look at how you use the boolean: error
    when is it false and when is it true?
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: nextInt - can not find InputMismatchException

    Yes it is ok.I found what was wrong.The boolean error was not reseted to false! Thank you very much for your answers

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