Anthony Pena

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since May 14, 2011

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Recent posts by Anthony Pena

palindrome checker, tried to debug, keeps looping why?

Hunter McMillen wrote:I'm glad that it works like that, but there is still a better way of solving this that doesn't require those additional variables. Remove those variables and try moving around where you increment i_Fstlet and decrement i_Laslet.

Hunter

after i compare.. that way it compares the first two letters then returns a value before it even increments

11 years ago

Applets

palindrome checker, tried to debug, keeps looping why?

Hunter McMillen wrote:Actually I was mistaken, the way you have your condition set up will work for both odd and even numbered palindromes. congrats.

Hunter

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class PalindromeCheck extends JApplet implements ActionListener{
JTextField tf_Userin;
JTextArea ta_Out;
JLabel l_Instruc;
JButton b_Check;
JPanel pane;
public void init()
{
setLayout (new FlowLayout());
l_Instruc = new JLabel("Enter a word to see if its a palindrome(only lower case)");
tf_Userin = new JTextField (10);
ta_Out = new JTextArea(1,10);
pane = new JPanel ();
b_Check = new JButton("Check");
b_Check.addActionListener(this);
add(l_Instruc); add(tf_Userin); add(pane); add(b_Check);add(ta_Out);
}
public void actionPerformed (ActionEvent ae)
{
Object src =ae.getSource();
String word = tf_Userin.getText();
int i_Fstlet;
int i_Laslet;
int i_Midlet;
int i_stLength;
int i_realFst;
int i_realLst;
int i_temp;
if (src==b_Check){
i_stLength=word.length();
i_Midlet =i_stLength/2;
i_Laslet =i_stLength-1;
i_Fstlet = 0;
i_realFst=0;
i_realLst=i_stLength-1;
boolean isPal;
while (i_Fstlet<=i_Midlet&&i_Laslet>=i_Midlet){
i_Fstlet+=1;i_Laslet-=1;
if (word.charAt(i_Fstlet)!=word.charAt(i_Laslet)||word.charAt(i_realFst)!=word.charAt(i_realLst)){
isPal=false;
ta_Out.setText(word+" is not a palindrome");
}else if (word.charAt(i_Fstlet)==word.charAt(i_Laslet)&&word.charAt(i_realFst)==word.charAt(i_realLst)){
isPal= true;
ta_Out.setText(word+" is a palindrome");
}
}
}
}}

woo got it working thanks for all the help really appreciate it

11 years ago

Applets

palindrome checker, tried to debug, keeps looping why?

Hunter McMillen wrote:Actually I was mistaken, the way you have your condition set up will work for both odd and even numbered palindromes. congrats.

Hunter

gah ok, well then how would i make it check against the first two letters and the middle two letters a case like bannah(just and example) my current code, would turn that out to be true

11 years ago

Applets

palindrome checker, tried to debug, keeps looping why?

Hunter McMillen wrote:There is a different case you will have to handle in your loop depending on whether the word you are looking at has an odd or even number of letters.

Hunter

so for example, if the first and the last letters dont match, i want to stop it there and say its not a palindrome right away,
if they do match but the next to letters dont i want to stop it there, etc etc.. hm

11 years ago

Applets

palindrome checker, tried to debug, keeps looping why?

Hunter McMillen wrote:

i need to increment both the end the first letter? but will this work for smaller words?

Try it out and let me know what you find.

Hunter

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class PalindromeCheck extends JApplet implements ActionListener{
JTextField tf_Userin;
JTextArea ta_Out;
JLabel l_Instruc;
JButton b_Check;
JPanel pane;
public void init()
{
setLayout (new FlowLayout());
l_Instruc = new JLabel("Enter a word to see if its a palindrome");
tf_Userin = new JTextField (10);
ta_Out = new JTextArea(1,10);
pane = new JPanel ();
b_Check = new JButton("Check");
b_Check.addActionListener(this);
add(l_Instruc); add(tf_Userin); add(pane); add(b_Check);add(ta_Out);
}
public void actionPerformed (ActionEvent ae)
{
Object src =ae.getSource();
String word = tf_Userin.getText();
int i_Fstlet;
int i_Laslet;
int i_Midlet;
int i_stLength;
if (src==b_Check){
i_stLength=word.length();
i_Midlet =i_stLength/2;
i_Laslet =i_stLength-1;
i_Fstlet = 0;
boolean isPal;
while (i_Fstlet<=i_Midlet&&i_Laslet>=i_Midlet){
i_Fstlet+=1;i_Laslet-=1;
if (word.charAt(i_Fstlet)!=word.charAt(i_Laslet)){
isPal=false;
ta_Out.setText(word+" is not a palindrome");
}else if (word.charAt(i_Fstlet)==word.charAt(i_Laslet)){
isPal= true;
ta_Out.setText(word+" is a palindrome");
}
}
}
}}

now, this works for the bigger words but any word with duplicate letters in the middle doesn't work (tried racecar and it returns true tried programming and it returned false but with the word cool it retured true..)

11 years ago

Applets

palindrome checker, tried to debug, keeps looping why?

Hunter McMillen wrote:correct, so look at your loop and trace what you are comparing by hand. I'll use the example word "hannah" and do the first letter.

position: 0 1 2 3 4 5 letter: h a n n a h compare( h and h )...MATCH!

which letter positions do you need to increment/decrement to compare ( a and a)??
which letter positions are you incrementing?

Hunter

i need to increment both the end the first letter? but will this work for smaller words?
and what would happen in the middle if in a word like middle for instance? the rest of the word doesn't match but the two middle letters do.. hmm

11 years ago

Applets

palindrome checker, tried to debug, keeps looping why?

Paul Clapham wrote:

Anthony Pena wrote:

Hunter McMillen wrote:hmm, well you aren't incrementing in the correct place. Try this, ignore the program for a bit and explain to me how you would determine whether a word was a palindrome on a piece of paper.

Hunter

you would compare the first and last, the second and second to last the third and third to last...
correct?

No, that isn't correct. You haven't said how or when you stop comparing. And your instructions don't make sense if there are only two letters, for example. You need to be clearer about such things.

well you stop comparing when you get to the middle of the word where both letters would be the same. if there are only to letters they would need to be the same?

11 years ago

Applets

palindrome checker, tried to debug, keeps looping why?

Hunter McMillen wrote:hmm, well you aren't incrementing in the correct place. Try this, ignore the program for a bit and explain to me how you would determine whether a word was a palindrome on a piece of paper.

Hunter

you would compare the first and last, the second and second to last the third and third to last...
correct?

11 years ago

Applets

palindrome checker, tried to debug, keeps looping why?

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class PalindromeCheck extends JApplet implements ActionListener{
JTextField tf_Userin;
JTextArea ta_Out;
JLabel l_Instruc;
JButton b_Check;
JPanel pane;
public void init()
{
setLayout (new FlowLayout());
l_Instruc = new JLabel("Enter a word to see if its a palindrome");
tf_Userin = new JTextField (10);
ta_Out = new JTextArea(1,10);
pane = new JPanel ();
b_Check = new JButton("Check");
b_Check.addActionListener(this);
add(l_Instruc); add(tf_Userin); add(pane); add(b_Check);add(ta_Out);
}
public void actionPerformed (ActionEvent ae)
{
Object src =ae.getSource();
String word = tf_Userin.getText();
int i_Fstlet;
int i_Laslet;
int i_Midlet;
int i_stLength;
if (src==b_Check){
i_stLength=word.length();
i_Midlet =i_stLength/2;
i_Laslet =i_stLength-1;
i_Fstlet = 0;
boolean isPal;
while (i_Fstlet<=i_Midlet&&i_Laslet>=i_Midlet){
i_Fstlet+=1;
if (word.charAt(i_Fstlet)!=word.charAt(i_Laslet)){
isPal=false;
ta_Out.setText(word+" is not a palindrome");
}else if (word.charAt(i_Fstlet)==word.charAt(i_Laslet)){
isPal= true;
ta_Out.setText(word+" is a palindrome");
}
}
}
}}

heres the new code, now its always set to true.. ill debug for a bit but any tips would be appreciated thanks in advance

11 years ago

Applets

palindrome checker, tried to debug, keeps looping why?

Hunter McMillen wrote:you never increment the positions of the letters you are comparing, so the program compares the first and last letter forever.

Hunter

thanks!! makes sense !! awesome

11 years ago

Applets

need some help understading why this is not working (palindrome loop)

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class PalindromeCheck extends JApplet implements ActionListener{
JTextField tf_Userin;
JTextArea ta_Out;
JLabel l_Instruc;
JButton b_Check;
JPanel pane;
public void init()
{
setLayout (new FlowLayout());
l_Instruc = new JLabel("Enter a word to see if its a palindrome");
tf_Userin = new JTextField (10);
ta_Out = new JTextArea(1,10);
pane = new JPanel ();
b_Check = new JButton("Check");
b_Check.addActionListener(this);
add(l_Instruc); add(tf_Userin); add(pane); add(b_Check);add(ta_Out);
}
public void actionPerformed (ActionEvent ae)
{
Object src =ae.getSource();
String word = tf_Userin.getText();
int i_Fstlet;
int i_Laslet;
int i_Midlet;
int i_stLength;
if (src==b_Check){
i_stLength=word.length();
i_Midlet =i_stLength/2;
i_Laslet =i_stLength-1;
i_Fstlet = 0;
boolean isPal;
while (i_Fstlet<=i_Midlet&&i_Laslet>=i_Midlet){
if (word.charAt(i_Fstlet)!=word.charAt(i_Laslet)){
isPal=false;
}else if (word.charAt(i_Fstlet)==word.charAt(i_Laslet)){
isPal= true;
}
if (isPal=false)
ta_Out.setText(word+" is not a palindrome");
else if (isPal=true)
ta_Out.setText(word+" is a palindrome");
}
}
}}

if anyone could tell me whats going on here, i ran it through the a debugger but i am not yet experianced enough to identify the issue and fix it, any tips would be appreciated. thanks!

11 years ago

Beginning Java

palindrome checker, tried to debug, keeps looping why?

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class PalindromeCheck extends JApplet implements ActionListener{
JTextField tf_Userin;
JTextArea ta_Out;
JLabel l_Instruc;
JButton b_Check;
JPanel pane;
public void init()
{
setLayout (new FlowLayout());
l_Instruc = new JLabel("Enter a word to see if its a palindrome");
tf_Userin = new JTextField (10);
ta_Out = new JTextArea(1,10);
pane = new JPanel ();
b_Check = new JButton("Check");
b_Check.addActionListener(this);
add(l_Instruc); add(tf_Userin); add(pane); add(b_Check);add(ta_Out);
}
public void actionPerformed (ActionEvent ae)
{
Object src =ae.getSource();
String word = tf_Userin.getText();
int i_Fstlet;
int i_Laslet;
int i_Midlet;
int i_stLength;
if (src==b_Check){
i_stLength=word.length();
i_Midlet =i_stLength/2;
i_Laslet =i_stLength-1;
i_Fstlet = 0;
boolean isPal;
while (i_Fstlet<=i_Midlet&&i_Laslet>=i_Midlet){
if (word.charAt(i_Fstlet)!=word.charAt(i_Laslet)){
isPal=false;
}else if (word.charAt(i_Fstlet)==word.charAt(i_Laslet)){
isPal= true;
}
if (isPal=false)
ta_Out.setText(word+" is not a palindrome");
else if (isPal=true)
ta_Out.setText(word+" is a palindrome");
}
}
}}

if anyone could tell me whats going on here, i ran it through the a debugger but i am not yet experianced enough to identify the issue and fix it,

any tips would be appreciated. thanks!

11 years ago

Applets

tictactoe help

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class tictactoe extends JApplet implements ActionListener
{
String sLetter = "";
JLabel jlWin= new JLabel(sLetter + " Wins!");
JLabel jlTie= new JLabel("NO ONE WINS!");
JButton b1,b2,b3,b4,b5,b6,b7,b8,b9;
JPanel pane = new JPanel();;
Image imageX; // marks field with 'x'
Image imageO; // marks field with 'o'
Image imageE; // marks field with '', empty
ImageIcon icE;
int iCount=0;
boolean bWin = false;
public void init()
{
imageX = getImage(getCodeBase(),"blcx.png");
imageO = getImage(getCodeBase(),"o.gif");
imageE = getImage(getCodeBase(),"empty.png");
icE=new ImageIcon(imageE);
b1= new JButton(icE);
b2= new JButton(icE);
b3= new JButton(icE);
b4= new JButton(icE);
b5= new JButton(icE);
b6= new JButton(icE);
b7= new JButton(icE);
b8= new JButton(icE);
b9= new JButton(icE);
pane.setLayout (new GridLayout(3,3));
pane.add (b1); pane.add (b2); pane.add (b3);
pane.add (b4); pane.add (b5); pane.add (b6);
pane.add (b7); pane.add (b8); pane.add (b9);
add (pane,BorderLayout.CENTER);
setFocusable(true);
b1.addActionListener(this);
b2.addActionListener(this);
b3.addActionListener(this);
b4.addActionListener(this);
b5.addActionListener(this);
b6.addActionListener(this);
b7.addActionListener(this);
b8.addActionListener(this);
b9.addActionListener(this);
}
public void actionPerformed(ActionEvent a)
{
iCount++;
if(iCount==1 || iCount == 3||iCount==5||iCount==7||iCount==9)
{
icE=new ImageIcon(imageX);
sLetter="X";
}
else if (iCount==2||iCount==4||iCount==6||iCount==8||iCount==10)
{
icE=new ImageIcon(imageO);
sLetter="O";
}
if (a.getSource()== b1)
{
b1.setText(sLetter);
b1.setIcon(icE);
b1.setEnabled(false);
}
else if (a.getSource()==b2)
{
b2.setText(sLetter);
b2.setIcon(icE);
b2.setEnabled(false);
}
else if (a.getSource()== b3)
{
b3.setText(sLetter);
b3.setIcon(icE);
b3.setEnabled(false);
}
else if (a.getSource()== b4)
{
b4.setText(sLetter);
b4.setIcon(icE);
b4.setEnabled(false);
}
else if (a.getSource()== b5)
{
b5.setText(sLetter);
b5.setIcon(icE);
b5.setEnabled(false);
}
else if (a.getSource()== b6)
{
b6.setText(sLetter);
b6.setIcon(icE);
b6.setEnabled(false);
}
else if (a.getSource()== b7)
{
b7.setText(sLetter);
b7.setIcon(icE);
b7.setEnabled(false);
}
else if (a.getSource()== b8)
{
b8.setText(sLetter);
b8.setIcon(icE);
b8.setEnabled(false);
}
else if (a.getSource()== b9)
{
b9.setText(sLetter);
b9.setIcon(icE);
b9.setEnabled(false);
}
//horizontal wins
if( b1.getText() == b2.getText() && b2.getText() == b3.getText() && b1.getText() != ""){
bWin = true;
b1.setBackground(Color.BLUE);
b2.setBackground(Color.BLUE);
b3.setBackground(Color.BLUE);
}
else if(b4.getText() == b5.getText() && b5.getText() == b6.getText() && b4.getText() != ""){
bWin = true;
b4.setBackground(Color.BLUE);
b5.setBackground(Color.BLUE);
b6.setBackground(Color.BLUE);
}
else if(b7.getText() == b8.getText() && b8.getText() == b9.getText() && b7.getText() != ""){
bWin = true;
b7.setBackground(Color.BLUE);
b8.setBackground(Color.BLUE);
b9.setBackground(Color.BLUE);
}
//vertical wins
else if(b1.getText() == b4.getText() && b4.getText() == b7.getText() && b1.getText() != ""){
bWin = true;
b1.setBackground(Color.BLUE);
b4.setBackground(Color.BLUE);
b7.setBackground(Color.BLUE);
}
else if(b2.getText() == b5.getText() && b5.getText() == b8.getText() && b2.getText() != ""){
bWin = true;
b2.setBackground(Color.BLUE);
b5.setBackground(Color.BLUE);
b8.setBackground(Color.BLUE);
}
else if(b3.getText() == b6.getText() && b6.getText() == b9.getText() && b3.getText() != ""){
bWin = true;
b3.setBackground(Color.BLUE);
b6.setBackground(Color.BLUE);
b9.setBackground(Color.BLUE);
}
//diagonal wins
else if(b1.getText() == b5.getText() && b5.getText() == b9.getText() && b1.getText() != ""){
bWin = true;
b1.setBackground(Color.BLUE);
b5.setBackground(Color.BLUE);
b9.setBackground(Color.BLUE);
}
else if(b3.getText() == b5.getText() && b5.getText() == b7.getText() && b3.getText() != ""){
bWin = true;
b3.setBackground(Color.BLUE);
b5.setBackground(Color.BLUE);
b7.setBackground(Color.BLUE);
}
else {
bWin = false;
}
if (bWin == true)
{
b1.setEnabled(false);
b2.setEnabled(false);
b3.setEnabled(false);
b4.setEnabled(false);
b5.setEnabled(false);
b6.setEnabled(false);
b7.setEnabled(false);
b8.setEnabled(false);
b9.setEnabled(false);
b5.setText(sLetter+" wins");
}
else if (iCount ==9 && bWin==false)
{
b1.setEnabled(false);
b2.setEnabled(false);
b3.setEnabled(false);
b4.setEnabled(false);
b5.setEnabled(false);
b6.setEnabled(false);
b7.setEnabled(false);
b8.setEnabled(false);
b9.setEnabled(false);
b5.setText("tie!");
}
}
}

so after alot of work thats what i got, it works, im happy lol

11 years ago

Beginning Java

tictactoe help

Campbell Ritchie wrote: . . . and have you done anything else with line 12?

im not sure what there is to do? i changed the name of the image to something more simple? should i try a different image?

11 years ago

Beginning Java

tictactoe help

Campbell Ritchie wrote:It looks as if the problem is on line 12.
You have made things difficult for yourself by trying to write the whole thing in one go. You ought to do it bit by bit.

Try printing the code base URL and the toString method of the Image to screen; then you can narrow down where the error occurs: is it code base or is it the image?

And the length of your actionPerformed method is a good example of why addActionListener(this) is poor, non-object-oriented programming. Even though there are lots of books which show such code.

java.lang.NullPointerException

at java.applet.Applet.getCodeBase(Applet.java:152)
at tictactoe.<init>(tictactoe.java:12)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at java.lang.Class.newInstance0(Class.java:355)
at java.lang.Class.newInstance(Class.java:308)
at sun.applet.AppletPanel.createApplet(AppletPanel.java:785)
at sun.applet.AppletPanel.runLoader(AppletPanel.java:714)
at sun.applet.AppletPanel.run(AppletPanel.java:368)
at java.lang.Thread.run(Thread.java:662)
thats the one with the issue i think

11 years ago

Beginning Java