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Thread: Problem with Loop

  1. #1
    Junior Member Dragonkndr712's Avatar
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    Default Problem with Loop

    I am new to java and in this assignment I need to make a spot to enter the customer's name and amount of kilowatt usage. I need to do this for three people, the first time through it works fine but after that there is no place to put the customer's name during the process. In our class we write it up in notebook and run from the command prompt. The input only appears in command prompt while output shows in the joption pane.

    //
     import javax.swing.JOptionPane;
    import java.util.Scanner;
     
    public class Electric1//Exercise 1 not complete
    {
    	public static void main(String args[])
    	{
    		Scanner input = new Scanner(System.in);
     
    		String name;
    		int kilowatts;
    		String message = "";
    		double pay;
     
     
    		System.out.print("What is your name?");
    		name =  input.nextLine();
     
    		kilowatts = System.out.print("How many kilowatts did you use?");
     
     
    		pay = kilowatts * .056;
     
    		message = String.format("%s, you owe $%.2f", name, pay);
     
    		JOptionPane.showMessageDialog(null, message);
    	}
    }


  2. #2
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    Cool Re: Problem with Loop

    kilowatts = System.out.print("How many kilowatts did you use?");

    That doesn't make any sense.

    The method println() is void...which means it doesn't return anything.

    However...this would work...but that's not what you're doing so don't use it....

    kilowats = Integer.parseInt(JOptionPane.showMessageDialog(null, "How many kilowatts did you use?" , "Enter Kilowatt usage", JOptionPane.QUESTION_MESSAGE));

    Your code...using command line...should be:
    System.out.println("How many kilowatts do you use?");
    kilowats = input.nextInt();

    To get output for three people...put your code in the for loop.

    Make sure to initialize all variables before starting the for loop.

    for (int i =0; i < 3; i++)
    {
     
    // put the code you have here and it will go through 3 times.
     
    }
    Last edited by javapenguin; February 1st, 2011 at 10:10 PM. Reason: Oops...made error on the for loop but fixed it. It's less than 3,not 2. My bad.

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    Dragonkndr712 (February 3rd, 2011)

  4. #3
    Junior Member Dragonkndr712's Avatar
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    Default Re: Problem with Loop

    Thank you for pointing out about kilowatt, you were right on that point but it still doesn't fix my problem. here is the new code, hopefully you can figure out where I am going wrong.

    //import javax.swing.JOptionPane;
    import java.util.Scanner;
     
    public class Electric1
    {
    	public static void main(String args[])
    	{
    		Scanner input = new Scanner(System.in);
     
    		String name;
    		int kilowatts;
    		String message = "";
    		double pay;
    		int counter = 1;
     
    		while(counter < 4)
    		{		
     
    			System.out.print("What is your name?");
    			name =  input.nextLine();
     
    			System.out.print("How many kilowatts did you use?");
    			kilowatts = input.nextInt();
     
    			pay = kilowatts * .056;
     
    			message = String.format("%s, you owe $%.2f", name, pay);
     
    			JOptionPane.showMessageDialog(null, message);
     
    			counter++;
    		}
    	}
    }

    I know I am doing something wrong but I can not see it. To me this looks right but like I said I am new to java.
    Last edited by Dragonkndr712; February 3rd, 2011 at 05:07 PM. Reason: code not going into Java area

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    Default Re: Problem with Loop

    What is your problem?

    What output are you getting?

    What output are you expecting?
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    Default Re: Problem with Loop

    If you remove "JOptionPane.showMessageDialog(null, message);" from your code, it will work fine, but I can't figure out why .
    Might be down to not specifying a parent, and its therefore not appearing in the foreground?
    With that in mind, It is late and you should take my guess with a very small pinch of salt ^^.
    Please use [highlight=Java]//code goes here...[/highlight] tags when posting your code

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    Default Re: Problem with Loop

    I also have this same exact problem for class. I used the information below and when i go to compile it ask the name and the watts for the first person just fine and then it will ask the name and watts for the second person all at one time. is there any advice that can help me with this?

    Here is my code
    import java.util.Scanner;
     
    public class Electric1
    {
        public static void main(String args[])
        {
            Scanner input = new Scanner(System.in);
     
            String name;
            int kilowatts;
            String message = "";
            double pay;
            int counter = 1;
     
            while(counter < 4)
            {       
    	    //Ask name
                System.out.print("What is your name?");
                name =  input.nextLine();
     
                System.out.print("How many kilowatts did you use?");
                kilowatts = input.nextInt();
     
                pay = kilowatts * .056;
     
                message = String.format("%s, you owe $%.2f", name, pay);
     
    	    JOptionPane.showMessageDialog(null, message);
     
                counter ++;
            }
        }
    }

  8. #7
    Junior Member Dragonkndr712's Avatar
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    Default Re: Problem with Loop

    Output expected is that in command prompt it will ask for the name and how kilowatts. It will then give the answer in the joptionpane. The first customer works fine but when the second time comes up it pushes pass the name and automatically goes to the kilowatt question.

    There has to be a joptionpane because that is the way the teacher wants it. Actually she said this will be how all our programs have to run.

    I have a capture of the command prompt.
    Attached Images Attached Images
    Last edited by Dragonkndr712; February 5th, 2011 at 06:48 PM. Reason: adding info

  9. #8
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    Default Re: Problem with Loop

    Quote Originally Posted by Dragonkndr712 View Post
    Output expected is that in command prompt it will ask for the name and how kilowatts. It will then give the answer in the joptionpane. The first customer works fine but when the second time comes up it pushes pass the name and automatically goes to the kilowatt question.

    There has to be a joptionpane because that is the way the teacher wants it. Actually she said this will be how all our programs have to run.

    I have a capture of the command prompt.
    I have the exact same homework. Not sure about your problem but i think its where your "name = input.nextLine(); remove Line and make it "name = input.next();" without quotations. Hopefully that works.

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    Default Re: Problem with Loop

    Quote Originally Posted by anthony23415 View Post
    I have the exact same homework. Not sure about your problem but i think its where your "name = input.nextLine(); remove Line and make it "name = input.next();" without quotations. Hopefully that works.
    Tried to do that with no luck..

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    Default Re: Problem with Loop

    Quote Originally Posted by Chappell817 View Post
    Tried to do that with no luck..
    This is what I did.

     
    import java.util.Scanner;
    import javax.swing.JOptionPane;
     
    public class Electric1
    {
        public static void main(String args[])
        {
            Scanner input = new Scanner(System.in);
     
            String name;
            int kilowatts;
            double total;
            int counter = 1;
     
            while(counter < 4)
            {       
            //Ask name
                System.out.println("What is your name?");
                name =  input.next();
                System.out.println("How many kilowatts did you use?");
                kilowatts = input.nextInt();
     
                total = kilowatts * .056;
     
                String message = String.format("%s $%.02f", name, total);
     
                JOptionPane.showMessageDialog(null, message);
     
                counter = counter + 1;
            }
        }
    }

  12. The Following User Says Thank You to anthony23415 For This Useful Post:

    Dragonkndr712 (February 7th, 2011)

  13. #11
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    Default Re: Problem with Loop

    Quote Originally Posted by anthony23415 View Post
    This is what I did.

     
    import java.util.Scanner;
    import javax.swing.JOptionPane;
     
    public class Electric1
    {
        public static void main(String args[])
        {
            Scanner input = new Scanner(System.in);
     
            String name;
            int kilowatts;
            double total;
            int counter = 1;
     
            while(counter < 4)
            {       
            //Ask name
                System.out.println("What is your name?");
                name =  input.next();
                System.out.println("How many kilowatts did you use?");
                kilowatts = input.nextInt();
     
                total = kilowatts * .056;
     
                String message = String.format("%s $%.02f", name, total);
     
                JOptionPane.showMessageDialog(null, message);
     
                counter = counter + 1;
            }
        }
    }
    Thanks i think you help me figure out what i was doing wrong..but not 100% sure..

  14. #12
    Junior Member Dragonkndr712's Avatar
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    Default Re: Problem with Loop

    That worked not sure why but my program works now. Thank you.

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    Default Re: Problem with Loop

    got that actually in class now trying to work on the second problem

  16. #14
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    Default Re: Problem with Loop

    Quote Originally Posted by Chappell817 View Post
    got that actually in class now trying to work on the second problem
    If you dont mind asking? You go to UTA? and have class at 9:30 am in room 255 for that java class?

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