How to create an array by inputting numbered into a textfield, Java applet

Question

My assignment is to input 20 numbers via a text field then out the mean, the median and the total using a while loop. I should be able to figure out the while loop myself, but I can't get the text field to input numbers into an array. Please help, here is my code so far:

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

public class whileloopq extends Applet implements ActionListener
{
    Label label;
    TextField input;
    int[] numArray = new int[20];
    int num;

    public void init ()
    {
        Label label = new Label("Enter numbers");
        TextField input = new TextField(5);
        add(label);
        add(input);
        input.addActionListener(this);
    }

    public void actionPerformed (ActionEvent ev)
    {
        int num = Integer.parseInt(input.getText());
        int index = 0;
        numArray[index] = num;
        index++;
        input.setText("");

    }

    public void paint (Graphics graf)
    {
        graf.drawString("Array" + numArray, 25, 85);
    }
}

Any help would be much appreciated.

FThompson · Accepted Answer · 2012-08-12 19:17:48Z

1

(Answer written under the assumption that this is a homework assignment.)

You know how to parse an integer from a string, as you show with your usage of Integer.parseInt, but you are calling it to parse the entire 20 characters as one integer. You need to get each character individually to be parsed.

I recommend using a for loop, and String#substring to substring the input text into several strings of length one.

Alternatively, you can split the input text around an empty string and then iterate through the resulting array (note that the first string in the array will be empty), but the other approach is more likely the one expected from someone new to Java, so you'll have to use your judgement here.

answered Aug 12, 2012 at 19:17

FThompson

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Comments

Pshemo · Accepted Answer · 2012-08-12 19:32:37Z

0

In actionPerformed() you are trying to read from class filed input.setText("");

but in init() you didn't initialized that field but created and added to applet local variable

TextField input = new TextField(5);

so class field is steal null. Change it to

input = new TextField(5);

edited Aug 12, 2012 at 19:32

answered Aug 12, 2012 at 19:26

Pshemo

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Dr. Varun Tiwari · Accepted Answer · 2021-05-27 05:57:12Z

0

import java.awt.*;
public class frame4array extends Frame
{
Checkbox c1[];
TextField t1[];
int i;
frame4array(String p)
{
super(p);
c1=new Checkbox[2];
t1=new TextField[2];
for(i=0;i<2;i++)
{
t1[0]=new TextField();
t1[0].setBounds(200, 50, 150, 30);
t1[1]=new TextField();
t1[1].setBounds(200, 80, 150, 30);
c1[0]=new Checkbox("Singing");
c1[0].setBackground(Color.red);
c1[0].setBounds(430,200,120,40);
c1[1]=new Checkbox("Cricket",true);
}
for(i=0;i<2;i++)
{
add(t1[i]);
add(c1[i]);
}
setFont(new Font("Arial",Font.ITALIC,40));
}
public static void main(String s[])
{
frame4array f1=new frame4array("hello");
f1.setSize(600,500);
f1.setVisible(true);
}

}

answered May 27, 2021 at 5:57

Dr. Varun Tiwari

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