a method to check if an input number is integer or float or NAN


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Thread: a method to check if an input number is integer or float or NAN

  1. #1
    Join Date
    Apr 2005
    Posts
    4

    a method to check if an input number is integer or float or NAN

    Hello,
    I am working on a program that inputs a data into a textfield and checks if the number is integer, float or Not a number. i have gotten the layout. But i have a rough idea that if it is an integer there would be no decimal points and decimal point for a float data and i fuser enters characters like "A" or "2M" then it's not a number. But this is my first class with strings and so have no idea how to approach this problem. Any guideline appreciated.I have just gotten a layout.

    import java.awt.*;
    import java.applet.*;
    import java.awt.event.*;

    public class Lab10a extends Applet
    implements ActionListener
    {

    private TextField inputTF;
    private String inputVal;

    public void init()
    {
    Label textLbl = new Label("A program to input a string and display the type of the number");
    inputTF = new TextField(7);

    add(textLbl);
    add(inputTF);

    inputTF.addActionListener(this);

    }

    public void actionPerformed(ActionEvent event)
    {
    if(event.getSource() == inputTF)
    inputVal = inputTF.getText().trim();

    repaint();
    }


    public void paint(Graphics g)
    {



    }
    }


    thanx,
    kt

  2. #2
    Join Date
    Dec 2004
    Location
    San Bernardino County, California
    Posts
    1,468
    the difficulty that I see is deciding on and then implementing the pattern your program will recognize as being an int or a float/double. The String class methods will allow you to distinguish whether a "token" is a number or not. What will involve your own evaluation and implementation will be how your program will decide whether a sting of digits will be interpreted as an integer or a float.

    What will be your "sign of the float"? How will you read that from the token?

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