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Thread: input.next and taking ints and doubles

  1. #1
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    Default input.next and taking ints and doubles

    Hi all,

    I am writing a program (weekly assignment) that takes numbers from a text file called Q2.txt, ignores white space, and gives the user a printout of the sum total and average of all the numbers in the text file.

    I have it working, but i can only make it work for doubles or integers only.
    I'll get full marks for what i have below, but for personal interest, i'd like to know how to make the program work for any and all number formats.

    How can i make it work for both ints and doubles?

    my Q2.txt is contains = 5.0 5.0 5.0 5.0

    Program returns : Average = 5.0, total = 20.0

    Thanks for any and all advice

    EDIT: I rewrote my test file Q2.txt with a mix of doubles and ints and it worked.
    So can i change my question to: Is this best practice? How can i improve this?



    import java.io.*;
    import java.util.Scanner;
     
    public class Q2
    {
    	//Open main method and throw any exceptions.
    	public static void main(String[] args)
    	throws Exception
    	{
    		//input from file called Q2.txt
    		Scanner input = new Scanner(new File("Q2.txt"));
    		//initialise variables for total and counter
    		double sum = 0.0;
    		int counter = 0;
    		//while there is still scores in the file unread, read them, add to the total and increment the counter
    		while (input.hasNext())
    		{
    			sum += input.nextDouble();
    			counter++;
    		}
    		//divide the sum by the counter
    		double average = sum / counter;
     
    		//print the results
    		System.out.println("The total of the scores in Q2.txt is " + sum);
    		System.out.println("The average of the scores in Q2.txt is " + average);
    		//close user input
    		input.close();
    	}
    }


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: input.next and taking ints and doubles

    The Scanner class has several different hasNext... methods that allow the program to see what kind of data is available to be read. Try using some of them with the matching next... method.
    If you don't understand my answer, don't ignore it, ask a question.

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