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Thread: How to limit users to enter only 12 digit input and an integer value in Java?

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    Default How to limit users to enter only 12 digit input and an integer value in Java?

    Hi Java professionals,
    I want to limit the program to only accept a 12 digit input and an integer value but I don't know how to program it,please help.

    import java.util.Scanner;
    public class testing4
    {
    public static void main(String []args)
    {
    Scanner reader = new Scanner(System.in);
    String input;

    do {
    System.out.print("Please enter a 12 digit number:");
    input = reader.nextLine();
    }while( input.length()!=12);
    System.out.println("Thanks.");
    }
    }


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    Default Re: How to limit users to enter only 12 digit input and an integer value in Java?

    hi,

    you can use the if condition after the getting input from the user.
    if(input.length()==12)
    {
    //allow
    }

    Still you have doubts or queries post here pls.

    Thanks,

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    Default Re: How to limit users to enter only 12 digit input and an integer value in Java?

    Hi,
    but I need to loop it if the input is incorrect,do you have any other advice?

    --- Update ---

    I mean the program needs to loop and it only accepts a numeric input.

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    Default Re: How to limit users to enter only 12 digit input and an integer value in Java?

    yes you can use your same condition in do..while
    do { 
    System.out.print("Please enter a 12 digit number:"); 
    input = reader.nextLine(); 
    if(input.length()==12){
    	//allow
     
    }
     
    }while( input.length()!=12);

    Thanks,

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    Default Re: How to limit users to enter only 12 digit input and an integer value in Java?

    Thanks but my program must not accept any letter or symbol and it must only accepts numbers,please advise.

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    Default Re: How to limit users to enter only 12 digit input and an integer value in Java?

    Hi,

    K do one thing, try to parse your input to integer using Integer.parseInt(your_input). Use try and catch statement.

    If you entered string means it throws an error in catch statement you can display "It is not a valid number" otherwise program flow goes well.

    do
    {
    try
    {
    //getInput
    //use Integer.parseInt(getInput) convert to int
    }
    catch(Exception e)
    {
    //Print "It is not a valid number"
    }
    }while(**Yourconditon**);

    If you face any difficulties post here. Happy to help

    Thanks,

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    Default Re: How to limit users to enter only 12 digit input and an integer value in Java?

    @Loh Jane: Please post your code in code/highlight tags. You can learn how with other useful info for newcomers at this link.

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