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Thread: Creating a scanner and putting input into arrays.

  1. #1
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    Default Creating a scanner and putting input into arrays.

    I'm trying to read user input from the terminal and separate the input into separate arrays depending on if the user input is an integer, scanner, or a string. The terminal should keep asking the user for input until the user types "quit". Please help!

    import java.util.*;
     
    public class arrayScanner
    {
        public static void main(String[] args)
        {
    	ArrayList<Integer> intList = new ArrayList<Integer>();
    	ArrayList<Double> doubleList = new ArrayList<Double>();
    	ArrayList<String> otherList = new ArrayList<String>();
     
            Scanner scanner = new Scanner(System.in);
    	System.out.println("Enter an int, double, any random text, or type \"quit\" to end:" );
    	String input = scanner.nextLine();
    	if(scanner.nextLine() == "quit")
    	{
                System.out.println("Integers: \n");
    	    for(int i = 0; i < intList.size(); i++)
    	    {
                    System.out.println("Integer list is" + intList.get(i));
    	    }
    	    System.out.println("Doubles: \n");
    	    for(int i = 0; i < doubleList.size(); i++)
    	    {
                    System.out.println("Double list is" + doubleList.get(i));
    	    }
    	    System.out.println("Other: \n");
    	    for(int i = 0; i < otherList.size(); i++)
    	    {
                    System.out.println("Other list is" + otherList.get(i));
    	    }
    	}
    	else if(scanner.hasNextInt())
    	{   
                intList.add(input);
    	}
    	else if(scanner.hasNextDouble())
    	{
                doubleList.add(input);
    	}
    	else if(scanner.hasNext())
    	{
                otherList.add(input);
    	}
     
        }
    }


  2. #2
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    Default Re: Creating a scanner and putting input into arrays.

    Please help!
    I and others can see what the problems with you code. but please give a specific questions. please specify what the problem is.

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    Default Re: Creating a scanner and putting input into arrays.

    for one, my compiler says "error: no suitable method found for add(String)" for intList.add(input); and doubleList.add(input);

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    Default Re: Creating a scanner and putting input into arrays.

    it is because the list intList was generic into Integer object only. therefore, it will accept Integer object or int primitive type (because of auto boxing I guess). and what you did in this statement of your code intList.add(input); is adding an element of Object String, your input variable is an Object reference variable for String object.

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    Default Re: Creating a scanner and putting input into arrays.

    oh. I thought I checked if it was an int with "else if(scanner.hasNextInt())" how would I use my scanner to determine the type of the user input?

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    Default Re: Creating a scanner and putting input into arrays.

    oh. I thought I checked if it was an int with "else if(scanner.hasNextInt())"
    yes, you checked it, but the problem is when adding an element to your intList, input is String. try to parse it in int. or other method
    intList.add(input); - that was the problem, adding an element of Object String but ArrayList was generic to Integer.

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