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Thread: User Input/Output for Math Calculations - Java

  1. #1
    Junior Member Infinite's Avatar
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    Default User Input/Output for Math Calculations - Java

    Hey everyone- I'm new here and this is my first forum post so I hope this is in the right place!
    I would appreciate all the help I can get:

    I'm trying to make a Java code to find the volume of a sphere but can't seem to use the user's input because I'm getting an error that "keyboard.readLine()" does not represent a real integer. I've attached my code below - I'm sure it's poorly written but I wouldn't know how to properly write it until I fix the input problem- I'd like to use the user's input in the volume equation which follows- thanks everyone!

    import java.io.*; // Stores information between user and computer.
    public class VolumeOfSphere
    {
    public static void main (String[] args) throws IOException

    {

    String radius;
    DataInputStream keyboard = new DataInputStream(System.in);
    System.out.println("What is the radius of the sphere: ");
    radius = keyboard.readLine();
    volume = ( 4.0 / 3.0 ) * Math.PI * Math.pow( radius, 3 );

    System.out.println("The volume of the sphere is: " + volume);


    }
    }


  2. #2
    Junior Member Infinite's Avatar
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    Default Simple error with math calculation code. Thanks!

    Hey everyone- I'm new here and this is my first forum post so I hope this is in the right place!
    I would appreciate all the help I can get:

    I'm trying to make a Java code to find the volume of a sphere but can't seem to use the user's input because I'm getting an error that "keyboard.readLine()" does not represent a real integer. I've attached my code below - I'm sure it's poorly written but I wouldn't know how to properly write it until I fix the input problem- I'd like to use the user's input in the volume equation which follows- thanks everyone!

    import java.io.*; // Stores information between user and computer.
    public class VolumeOfSphere
    {
    public static void main (String[] args) throws IOException

    {

    String radius;
    DataInputStream keyboard = new DataInputStream(System.in);
    System.out.println("What is the radius of the sphere: ");
    radius = keyboard.readLine();
    volume = ( 4.0 / 3.0 ) * Math.PI * Math.pow( radius, 3 );

    System.out.println("The volume of the sphere is: " + volume);


    }
    }

  3. #3
    Super Moderator jps's Avatar
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    Default Re: User Input/Output for Math Calculations - Java

    Welcome Infinite

    Please see the Announcements page for the use of code tags

    Look at the Scanner (Java 2 Platform SE 5.0) for getting keyboard input and the tutorials on basic IO and the sub-section on scanner

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    Super Moderator jps's Avatar
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    Default Re: Simple error with math calculation code. Thanks!

    Please do not waste everyone's time double posting questions.

    Threads merged

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    Default Simple error with I/O calculation code.

    Hey everyone- I'm new here and this is my first forum post so I hope this is in the right place!
    I would appreciate all the help I can get:

    I'm trying to make a Java code to find the volume of a sphere but can't seem to use the user's input because I'm getting an error that "keyboard.readLine()" does not represent a real integer. I've attached my code below - I'm sure it's poorly written but I wouldn't know how to properly write it until I fix the input problem- I'd like to use the user's input in the volume equation which follows- thanks everyone!

    import java.io.*; // Stores information between user and computer.
    public class VolumeOfSphere
    {
    public static void main (String[] args) throws IOException
     
    {
     
    String radius;
    DataInputStream keyboard = new DataInputStream(System.in);
    System.out.println("What is the radius of the sphere: ");
    radius = keyboard.readLine();
    volume = ( 4.0 / 3.0 ) * Math.PI * Math.pow( radius, 3 ); 
     
    System.out.println("The volume of the sphere is: " + volume);
     
     
    }
    }

  6. #6
    Super Moderator jps's Avatar
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    Default Re: User Input/Output for Math Calculations - Java

    Again with the duplicate posts.
    threads merged
    again

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    Default Re: User Input/Output for Math Calculations - Java

    "I'm getting an error that "keyboard.readLine()" does not represent a real integer."

    its telling you your error is with that line so look at the scanner link jps provided and see if there is one that deals with integers

    also just a little bit of info when you are dealing with number variables you will use (int, long, float, double...etc)

  8. #8
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    Default

    To read an integer you should use .readInt.. There are different methods for each datatype..

    For a string = readline
    For a integer = readInt

    And so on..

    Hope this helps

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