Programming Forums > Application Development > Java

kewlgeye · Apr 12th, 2008, 7:02 PM

Ok folks,

I have been working on this code for a long time, first it was a random number generator, and now I am trying to modify my code to generate a letter between A-J, or 10 letters, I thought I had this nailed, but I was wrong, I am very knew to java, so I don't really understand what I am doing, I know I received an error about string comparison, or something like that and it points to the "*" in the random generator part. I don't know what to do, I tried storing the string Letters in num, and then generating a random number that would recognize when a letter was inputted. Please help. This code is driving me crazy.

 JAVA Syntax (Toggle Plain Text) 
import java.util.*;
import javax.swing.JOptionPane;
 
 
public class guessing2
{
static Scanner console = new Scanner(System.in);
 
public static void main (String[] args)
{
//declare the variables
int num; //variable to store the random number
Double guess; // variable to store the number guess by user
boolean done;
String input;
String correct;
String coroutput;
String wrong;
String yguess;
int noOfGuesses = 0;
String[] Letters = {"A", "B", "C", "D", "E", "F", "G", "H", "I", "J"};
 
 
Letters[num] = (Math.random() * 10);
done = false;
 
while ((noOfGuesses < 3) && (!done))
{
yguess = JOptionPane.showInputDialog("Please enter a letter beween A-J or number between 1-10");
guess = Double.parseDouble(yguess);
noOfGuesses++;
 
if (guess == num)
 
{
 
coroutput = "Congratulations you guessed it";
JOptionPane.showMessageDialog(null, coroutput,
	"Congratulations", JOptionPane.INFORMATION_MESSAGE);
done = true;
}
else
if (guess < num)
{
JOptionPane.showMessageDialog(null, "You're too low!",
	"Failure", JOptionPane.INFORMATION_MESSAGE);
}
else
if (guess > num)
{
JOptionPane.showMessageDialog(null, "You're too high!",
	"Failure", JOptionPane.INFORMATION_MESSAGE);
}
else
if (!done)
{
JOptionPane.showMessageDialog(null, "You lose, Too many Tries, Correct number = " + num,
	"Failure", JOptionPane.INFORMATION_MESSAGE);
}
 
 
} //end while
}
}
import java.util.*;
import javax.swing.JOptionPane;


public class guessing2
{
static Scanner console = new Scanner(System.in);

public static void main (String[] args)
{
//declare the variables
int num; //variable to store the random number
Double guess; // variable to store the number guess by user
boolean done;
String input;
String correct;
String coroutput;
String wrong;
String yguess;
int noOfGuesses = 0;
String[] Letters = {"A", "B", "C", "D", "E", "F", "G", "H", "I", "J"};


Letters[num] = (Math.random() * 10);
done = false;

while ((noOfGuesses < 3) && (!done))
{
yguess = JOptionPane.showInputDialog("Please enter a letter beween A-J or number between 1-10");
guess = Double.parseDouble(yguess);
noOfGuesses++;

if (guess == num)

{

coroutput = "Congratulations you guessed it";
JOptionPane.showMessageDialog(null, coroutput,
	"Congratulations", JOptionPane.INFORMATION_MESSAGE);
done = true;
}
else
if (guess < num)
{
JOptionPane.showMessageDialog(null, "You're too low!",
	"Failure", JOptionPane.INFORMATION_MESSAGE);
}
else
if (guess > num)
{
JOptionPane.showMessageDialog(null, "You're too high!",
	"Failure", JOptionPane.INFORMATION_MESSAGE);
}
else
if (!done)
{
JOptionPane.showMessageDialog(null, "You lose, Too many Tries, Correct number = " + num,
	"Failure", JOptionPane.INFORMATION_MESSAGE);
}


} //end while
}
}

Ooble · Apr 12th, 2008, 8:40 PM

You need to sort out your code tags (or get a moderator to do it if you can no longer edit your post). Delete the current tags, highlight the code and click the [#] button on the toolbar.

kewlgeye · Apr 12th, 2008, 8:55 PM

I will remember this next time, I am not able to fix it myself, but from the looks of it everything printed fine this time, but I will try again next time to do it right. I made this mistake before and thought I was doing it right, but I guess I messed up. Still open to suggestions regarding the post though.

Ancient Dragon · Apr 12th, 2008, 10:28 PM

you almost got the code tags right. Here is how to do it. Note that there are no spaces anywhere within the brackets.

[code=java]
// your code here
[/code]

I fixed up the code tags, but they don't help when you have crappy formatting style.

kewlgeye · Apr 12th, 2008, 10:45 PM

I have been working more on this, and here is the code I have now. But I am receiving this error.

"operator * cannot be applied to double.java.lang.String[]"

I can't figure it out, does any one know how I can fix this?

 java Syntax (Toggle Plain Text) 
import java.util.*;
import javax.swing.JOptionPane;
 
 
public class guessing
{
static Scanner console = new Scanner(System.in);
 
public static void main (String[] args)
{
//declare the variables
int num; //variable to store the random number
double guess; // variable to store the number guess by user
boolean done;
String input;
String correct;
String coroutput;
String wrong;
String yguess;
int noOfGuesses = 0;
String[] max = {"A", "B", "C", "D", "E", "F", "G", "H", "I", "J"};
 
int rand = (int) (Math.random() * max)+1;
num = (int) (Math.random() * 10);
done = false;
 
while ((noOfGuesses < 3) && (!done))
	{
		yguess = JOptionPane.showInputDialog("Please enter a letter beween A-J or number between 1-10");
		guess = Double.parseDouble(yguess);
		noOfGuesses++;
if (guess == num)
	{
		coroutput = "Congratulations you guessed it";
		JOptionPane.showMessageDialog(null, coroutput,
		"Congratulations", JOptionPane.INFORMATION_MESSAGE);
		done = true;
	}
else
if (guess < num)
	{
		JOptionPane.showMessageDialog(null, "You're too low!",
		"Failure", JOptionPane.INFORMATION_MESSAGE);
	}
else
if (guess > num)
	{
		JOptionPane.showMessageDialog(null, "You're too high!",
		"Failure", JOptionPane.INFORMATION_MESSAGE);
	}
 
if (noOfGuesses == 3)
	{
		JOptionPane.showMessageDialog(null, "You lose, Too many Tries, Correct number = " + num,
		"Failure", JOptionPane.INFORMATION_MESSAGE);
	}
 
 
	} //end while
    }
}
import java.util.*;
import javax.swing.JOptionPane;


public class guessing
{
static Scanner console = new Scanner(System.in);

public static void main (String[] args)
{
//declare the variables
int num; //variable to store the random number
double guess; // variable to store the number guess by user
boolean done;
String input;
String correct;
String coroutput;
String wrong;
String yguess;
int noOfGuesses = 0;
String[] max = {"A", "B", "C", "D", "E", "F", "G", "H", "I", "J"};

int rand = (int) (Math.random() * max)+1;
num = (int) (Math.random() * 10);
done = false;

while ((noOfGuesses < 3) && (!done))
	{
		yguess = JOptionPane.showInputDialog("Please enter a letter beween A-J or number between 1-10");
		guess = Double.parseDouble(yguess);
		noOfGuesses++;
if (guess == num)
	{
		coroutput = "Congratulations you guessed it";
		JOptionPane.showMessageDialog(null, coroutput,
		"Congratulations", JOptionPane.INFORMATION_MESSAGE);
		done = true;
	}
else
if (guess < num)
	{
		JOptionPane.showMessageDialog(null, "You're too low!",
		"Failure", JOptionPane.INFORMATION_MESSAGE);
	}
else
if (guess > num)
	{
		JOptionPane.showMessageDialog(null, "You're too high!",
		"Failure", JOptionPane.INFORMATION_MESSAGE);
	}

if (noOfGuesses == 3)
	{
		JOptionPane.showMessageDialog(null, "You lose, Too many Tries, Correct number = " + num,
		"Failure", JOptionPane.INFORMATION_MESSAGE);
	}


	} //end while
    }
}

titaniumdecoy · Apr 12th, 2008, 10:59 PM

Look at line 23. You are multiplying Math.random() by a String[] (max), exactly as the error message states. You probably meant to write max.length.

manny85 · Apr 12th, 2008, 11:40 PM

First post on this forum but I have been lurking for a while. It has been a few years since I have used Java so thought I'd give this a go for some practice. Here is what I came up with based largely on your code. References are at the bottom.

 java Syntax (Toggle Plain Text) 
import java.util.*;
import javax.swing.JOptionPane;
 
 
public class guessing2
{
static Scanner console = new Scanner(System.in);
 
private static boolean isNumeric(String checkStr)
// determine if string is numeric
{
	try{
		Integer.parseInt(checkStr);
		return true; //Did not throw, must be a number
	}catch(NumberFormatException err){
		return false; //Threw, So is not a number
	}
}
public static void main (String[] args)
{
 
	int numGuesses = 0, uiInt = 0;
	boolean done = false;
	int rndNum = (int)(10.0 * Math.random());
	String uiStr = "", rndGuess = ""; 
	char firstChar;
	String[] Letters = {"A", "B", "C", "D", "E", "F", "G", "H", "I", "J"};
	rndGuess = Letters[rndNum];
 
	while ((numGuesses < 3) && !done)
	{
		uiStr = JOptionPane.showInputDialog("Please enter a letter beween A-J or number between 1-10");
		uiStr = uiStr.toUpperCase();
		if(isNumeric(uiStr))
		// check if user input was numeric
		// parse string input to integer and subtract 
		// one in order to compare with rndNum
		// retrieve letter based on numeric input to 
		// compare against rndGuess
		{
			uiInt = Integer.parseInt(uiStr) - 1;
			uiStr = Letters[uiInt];
		}
		else
		{
		// if is isn't numeric pull first character 
		// from user input into firstChar
		// then based on that store the numeric value 
		// in uiInt for comparison with rndNum
			firstChar = uiStr.charAt(0);
			switch(firstChar)
			{
			case 'A':
				uiInt = 0;
				break;
			case 'B':
				uiInt = 1;
				break;
			case 'C':
				uiInt = 2;
				break;
			case 'D':
				uiInt = 3;
				break;
			case 'E':
				uiInt = 4;
				break;
			case 'F':
				uiInt = 5;
				break;
			case 'G':
				uiInt = 6;
				break;
			case 'H':
				uiInt = 7;
				break;
			case 'I':
				uiInt = 8;
				break;
			case 'J':
				uiInt = 9;
				break;
			default:
				JOptionPane.showMessageDialog(null, "Invalid Character Input", "Invalid Input", JOptionPane.INFORMATION_MESSAGE);
				done = true;
				break;
			}
		}
 
			if (uiInt < rndNum | uiStr.compareTo(rndGuess) < 0)
				JOptionPane.showMessageDialog(null, "You're too low!", "Failure", JOptionPane.INFORMATION_MESSAGE);
			else
			if (uiInt > rndNum | uiStr.compareTo(rndGuess) > 0)
				JOptionPane.showMessageDialog(null, "You're too high!", "Failure", JOptionPane.INFORMATION_MESSAGE);
			else
				JOptionPane.showMessageDialog(null, "Congratulations you guessed it", "Congratulations", JOptionPane.INFORMATION_MESSAGE);
				done = true;
			numGuesses++;
		} //end while
 
	if (numGuesses == 3)
		JOptionPane.showMessageDialog(null, "You lose, Too many Tries, Correct Letter = " + Letters[rndNum] + " and Correct Number = " + rndNum++, "Failure", JOptionPane.INFORMATION_MESSAGE);
	}
	}
import java.util.*;
import javax.swing.JOptionPane;


public class guessing2
{
static Scanner console = new Scanner(System.in);

private static boolean isNumeric(String checkStr)
// determine if string is numeric
{
	try{
		Integer.parseInt(checkStr);
		return true; //Did not throw, must be a number
	}catch(NumberFormatException err){
		return false; //Threw, So is not a number
	}
}
public static void main (String[] args)
{

	int numGuesses = 0, uiInt = 0;
	boolean done = false;
	int rndNum = (int)(10.0 * Math.random());
	String uiStr = "", rndGuess = ""; 
	char firstChar;
	String[] Letters = {"A", "B", "C", "D", "E", "F", "G", "H", "I", "J"};
	rndGuess = Letters[rndNum];

	while ((numGuesses < 3) && !done)
	{
		uiStr = JOptionPane.showInputDialog("Please enter a letter beween A-J or number between 1-10");
		uiStr = uiStr.toUpperCase();
		if(isNumeric(uiStr))
		// check if user input was numeric
		// parse string input to integer and subtract 
		// one in order to compare with rndNum
		// retrieve letter based on numeric input to 
		// compare against rndGuess
		{
			uiInt = Integer.parseInt(uiStr) - 1;
			uiStr = Letters[uiInt];
		}
		else
		{
		// if is isn't numeric pull first character 
		// from user input into firstChar
		// then based on that store the numeric value 
		// in uiInt for comparison with rndNum
			firstChar = uiStr.charAt(0);
			switch(firstChar)
			{
			case 'A':
				uiInt = 0;
				break;
			case 'B':
				uiInt = 1;
				break;
			case 'C':
				uiInt = 2;
				break;
			case 'D':
				uiInt = 3;
				break;
			case 'E':
				uiInt = 4;
				break;
			case 'F':
				uiInt = 5;
				break;
			case 'G':
				uiInt = 6;
				break;
			case 'H':
				uiInt = 7;
				break;
			case 'I':
				uiInt = 8;
				break;
			case 'J':
				uiInt = 9;
				break;
			default:
				JOptionPane.showMessageDialog(null, "Invalid Character Input", "Invalid Input", JOptionPane.INFORMATION_MESSAGE);
				done = true;
				break;
			}
		}

			if (uiInt < rndNum | uiStr.compareTo(rndGuess) < 0)
				JOptionPane.showMessageDialog(null, "You're too low!", "Failure", JOptionPane.INFORMATION_MESSAGE);
			else
			if (uiInt > rndNum | uiStr.compareTo(rndGuess) > 0)
				JOptionPane.showMessageDialog(null, "You're too high!", "Failure", JOptionPane.INFORMATION_MESSAGE);
			else
				JOptionPane.showMessageDialog(null, "Congratulations you guessed it", "Congratulations", JOptionPane.INFORMATION_MESSAGE);
				done = true;
			numGuesses++;
		} //end while
	
	if (numGuesses == 3)
		JOptionPane.showMessageDialog(null, "You lose, Too many Tries, Correct Letter = " + Letters[rndNum] + " and Correct Number = " + rndNum++, "Failure", JOptionPane.INFORMATION_MESSAGE);
	}
	}

The reason I choose the Switch statement was mainly because I don't think that if a user inputs a letter that ".parseDouble" converts it to a numeric value. So my reasoning was that if they only guess letters they'll never succeed with that system. Please correct me if I'm wrong in that logic.

-Manny

http://www.leepoint.net/notes-java/a...andom-api.html

http://bytes.com/forum/thread17584.html ---isNumeric() function
http://www.roseindia.net/java/master...twise-or.shtml
http://www.leepoint.net/notes-java/d...goverview.html
http://www.javabeginner.com/java-string-comparison.htm
http://forum.java.sun.com/thread.jsp...sageID=9698690 ---Converting letters to numbers
http://java.sun.com/docs/books/tutor...ipstrings.html

titaniumdecoy · Apr 13th, 2008, 12:15 AM

Quote:

Originally Posted by manny85

The reason I choose the Switch statement was mainly because I don't think that if a user inputs a letter that ".parseDouble" converts it to a numeric value. So my reasoning was that if they only guess letters they'll never succeed with that system. Please correct me if I'm wrong in that logic.[/url]

The Double.parseDouble function will convert a String to a double. However, you are correct in that floating-point numbers are inherently inexact and as such any comparisons involving a floating-point number is likely to yield incorrect results.

manny85 · Apr 13th, 2008, 12:55 AM

Actually I don't think I made it very clear what I meant now that I reread my last post. I agree that using Double.parseDouble will convert a string, which contains a number (1-10 in our case), to an actual double. However if a string is storing a set a characters, in this case A-J, then I don't think Double.parseDouble will take that character and convert it to its/a numerical form. If it does in fact do that what values do the A-J end up being (numerically)...0-9, 1-10, ASCII values? Hope that makes more sense and also explains to kewlgeye why I choose the switch statement because I don't think his current program will respond correctly if a user inputs a character.

Side note: Kewlgeye, are you trying to generate two separate random values meaning a random letter and a separate random number? In my code above I'm using the randomly generated number to retrieve the corresponding letter. So if a user inputs either the correct number or letter they win (1 or A, 2 or B, 3 or C, ... , 10 or J).

kewlgeye · Apr 13th, 2008, 10:32 AM

Quote:

Originally Posted by manny85

Side note: Kewlgeye, are you trying to generate two separate random values meaning a random letter and a separate random number? In my code above I'm using the randomly generated number to retrieve the corresponding letter. So if a user inputs either the correct number or letter they win (1 or A, 2 or B, 3 or C, ... , 10 or J).

I am trying to pull up a window that allows a user to enter a number or a letter between 1-10 or A-J and depending on what they choose, the program will generate a random number or letter depending on the users first input.

The user types A a new window pops up and asks you to guess a letter between A-J and you have 3 trys, if you enter z or a lowercase then you receive an error window.

If the user enters 2 in the first window then you are taken to a new window that asks you to guess a number between 1-10 and you have 3 trys, likewise, if you enter 20 you will receive an invalid number error in a window, otherwise the program terminates with a window that says "Sorry you had three tries, the number or letter was "?" <------- whatever the number or letter was, but it should not display both random number or letter, just the one that you were guessing on.

Thank you all for your help and recommendations on this.

Manny, I tried your program and it works great, it should just show the letter or number though, and the letters are ok, but the numbers are 1 behind, meaning that if the actual number to be guessed is 4 I should enter a 5 in order to get it correct. But way to go, the program itself works. Nice job!

Apr 12th, 2008, 7:02 PM	#1
kewlgeye Programmer Join Date: Jan 2008 Posts: 53 Rep Power: 1	Random "Letter" Generator Ok folks, I have been working on this code for a long time, first it was a random number generator, and now I am trying to modify my code to generate a letter between A-J, or 10 letters, I thought I had this nailed, but I was wrong, I am very knew to java, so I don't really understand what I am doing, I know I received an error about string comparison, or something like that and it points to the "" in the random generator part. I don't know what to do, I tried storing the string Letters in num, and then generating a random number that would recognize when a letter was inputted. Please help. This code is driving me crazy. JAVA Syntax* (Toggle Plain Text) import java.util.; import javax.swing.JOptionPane; public class guessing2 { static Scanner console = new Scanner(System.in); public static void main (String[] args) { //declare the variables int num; //variable to store the random number Double guess; // variable to store the number guess by user boolean done; String input; String correct; String coroutput; String wrong; String yguess; int noOfGuesses = 0; String[] Letters = {"A", "B", "C", "D", "E", "F", "G", "H", "I", "J"}; Letters[num] = (Math.random() 10); done = false; while ((noOfGuesses < 3) && (!done)) { yguess = JOptionPane.showInputDialog("Please enter a letter beween A-J or number between 1-10"); guess = Double.parseDouble(yguess); noOfGuesses++; if (guess == num) { coroutput = "Congratulations you guessed it"; JOptionPane.showMessageDialog(null, coroutput, "Congratulations", JOptionPane.INFORMATION_MESSAGE); done = true; } else if (guess < num) { JOptionPane.showMessageDialog(null, "You're too low!", "Failure", JOptionPane.INFORMATION_MESSAGE); } else if (guess > num) { JOptionPane.showMessageDialog(null, "You're too high!", "Failure", JOptionPane.INFORMATION_MESSAGE); } else if (!done) { JOptionPane.showMessageDialog(null, "You lose, Too many Tries, Correct number = " + num, "Failure", JOptionPane.INFORMATION_MESSAGE); } } //end while } } import java.util.; import javax.swing.JOptionPane; public class guessing2 { static Scanner console = new Scanner(System.in); public static void main (String[] args) { //declare the variables int num; //variable to store the random number Double guess; // variable to store the number guess by user boolean done; String input; String correct; String coroutput; String wrong; String yguess; int noOfGuesses = 0; String[] Letters = {"A", "B", "C", "D", "E", "F", "G", "H", "I", "J"}; Letters[num] = (Math.random() 10); done = false; while ((noOfGuesses < 3) && (!done)) { yguess = JOptionPane.showInputDialog("Please enter a letter beween A-J or number between 1-10"); guess = Double.parseDouble(yguess); noOfGuesses++; if (guess == num) { coroutput = "Congratulations you guessed it"; JOptionPane.showMessageDialog(null, coroutput, "Congratulations", JOptionPane.INFORMATION_MESSAGE); done = true; } else if (guess < num) { JOptionPane.showMessageDialog(null, "You're too low!", "Failure", JOptionPane.INFORMATION_MESSAGE); } else if (guess > num) { JOptionPane.showMessageDialog(null, "You're too high!", "Failure", JOptionPane.INFORMATION_MESSAGE); } else if (!done) { JOptionPane.showMessageDialog(null, "You lose, Too many Tries, Correct number = " + num, "Failure", JOptionPane.INFORMATION_MESSAGE); } } //end while } } Last edited by Ancient Dragon; Apr 12th, 2008 at 10:26 PM. Reason: corrected code tags

Apr 12th, 2008, 8:40 PM	#2
Ooble I eat cake for breakfast. Join Date: Jul 2004 Location: In my box. Posts: 4,434 Rep Power: 9	Re: Random "Letter" Generator You need to sort out your code tags (or get a moderator to do it if you can no longer edit your post). Delete the current tags, highlight the code and click the [#] button on the toolbar. __________________ Me :: You :: Them

Apr 12th, 2008, 8:55 PM	#3
kewlgeye Programmer Join Date: Jan 2008 Posts: 53 Rep Power: 1	Re: Random "Letter" Generator I will remember this next time, I am not able to fix it myself, but from the looks of it everything printed fine this time, but I will try again next time to do it right. I made this mistake before and thought I was doing it right, but I guess I messed up. Still open to suggestions regarding the post though.

Apr 12th, 2008, 10:28 PM	#4
Ancient Dragon PFO God In Training Join Date: Jun 2005 Location: near St Louis, MO. (USA) Posts: 499 Rep Power: 4	Re: Random "Letter" Generator you almost got the code tags right. Here is how to do it. Note that there are no spaces anywhere within the brackets. [code=java] // your code here [/code] I fixed up the code tags, but they don't help when you have crappy formatting style. __________________ I Like Ike. Vote for Dwight Eisenhower this November. --This message brought to you by the the Procrastinators Club Of America.

Apr 12th, 2008, 10:45 PM	#5
kewlgeye Programmer Join Date: Jan 2008 Posts: 53 Rep Power: 1	Re: Random "Letter" Generator I have been working more on this, and here is the code I have now. But I am receiving this error. "operator * cannot be applied to double.java.lang.String[]" I can't figure it out, does any one know how I can fix this? java Syntax (Toggle Plain Text) import java.util.; import javax.swing.JOptionPane; public class guessing { static Scanner console = new Scanner(System.in); public static void main (String[] args) { //declare the variables int num; //variable to store the random number double guess; // variable to store the number guess by user boolean done; String input; String correct; String coroutput; String wrong; String yguess; int noOfGuesses = 0; String[] max = {"A", "B", "C", "D", "E", "F", "G", "H", "I", "J"}; int rand = (int) (Math.random() max)+1; num = (int) (Math.random() * 10); done = false; while ((noOfGuesses < 3) && (!done)) { yguess = JOptionPane.showInputDialog("Please enter a letter beween A-J or number between 1-10"); guess = Double.parseDouble(yguess); noOfGuesses++; if (guess == num) { coroutput = "Congratulations you guessed it"; JOptionPane.showMessageDialog(null, coroutput, "Congratulations", JOptionPane.INFORMATION_MESSAGE); done = true; } else if (guess < num) { JOptionPane.showMessageDialog(null, "You're too low!", "Failure", JOptionPane.INFORMATION_MESSAGE); } else if (guess > num) { JOptionPane.showMessageDialog(null, "You're too high!", "Failure", JOptionPane.INFORMATION_MESSAGE); } if (noOfGuesses == 3) { JOptionPane.showMessageDialog(null, "You lose, Too many Tries, Correct number = " + num, "Failure", JOptionPane.INFORMATION_MESSAGE); } } //end while } } import java.util.; import javax.swing.JOptionPane; public class guessing { static Scanner console = new Scanner(System.in); public static void main (String[] args) { //declare the variables int num; //variable to store the random number double guess; // variable to store the number guess by user boolean done; String input; String correct; String coroutput; String wrong; String yguess; int noOfGuesses = 0; String[] max = {"A", "B", "C", "D", "E", "F", "G", "H", "I", "J"}; int rand = (int) (Math.random() max)+1; num = (int) (Math.random() * 10); done = false; while ((noOfGuesses < 3) && (!done)) { yguess = JOptionPane.showInputDialog("Please enter a letter beween A-J or number between 1-10"); guess = Double.parseDouble(yguess); noOfGuesses++; if (guess == num) { coroutput = "Congratulations you guessed it"; JOptionPane.showMessageDialog(null, coroutput, "Congratulations", JOptionPane.INFORMATION_MESSAGE); done = true; } else if (guess < num) { JOptionPane.showMessageDialog(null, "You're too low!", "Failure", JOptionPane.INFORMATION_MESSAGE); } else if (guess > num) { JOptionPane.showMessageDialog(null, "You're too high!", "Failure", JOptionPane.INFORMATION_MESSAGE); } if (noOfGuesses == 3) { JOptionPane.showMessageDialog(null, "You lose, Too many Tries, Correct number = " + num, "Failure", JOptionPane.INFORMATION_MESSAGE); } } //end while } }

Apr 12th, 2008, 10:59 PM	#6
titaniumdecoy Expert Programmer Join Date: Nov 2005 Posts: 837 Rep Power: 3	Re: Random "Letter" Generator Look at line 23. You are multiplying Math.random() by a String[] (max), exactly as the error message states. You probably meant to write max.length.

Apr 12th, 2008, 11:40 PM	#7
manny85 Newbie Join Date: Apr 2008 Location: Ft Meade MD Posts: 6 Rep Power: 0	Re: Random "Letter" Generator First post on this forum but I have been lurking for a while. It has been a few years since I have used Java so thought I'd give this a go for some practice. Here is what I came up with based largely on your code. References are at the bottom. java Syntax (Toggle Plain Text) import java.util.; import javax.swing.JOptionPane; public class guessing2 { static Scanner console = new Scanner(System.in); private static boolean isNumeric(String checkStr) // determine if string is numeric { try{ Integer.parseInt(checkStr); return true; //Did not throw, must be a number }catch(NumberFormatException err){ return false; //Threw, So is not a number } } public static void main (String[] args) { int numGuesses = 0, uiInt = 0; boolean done = false; int rndNum = (int)(10.0 Math.random()); String uiStr = "", rndGuess = ""; char firstChar; String[] Letters = {"A", "B", "C", "D", "E", "F", "G", "H", "I", "J"}; rndGuess = Letters[rndNum]; while ((numGuesses < 3) && !done) { uiStr = JOptionPane.showInputDialog("Please enter a letter beween A-J or number between 1-10"); uiStr = uiStr.toUpperCase(); if(isNumeric(uiStr)) // check if user input was numeric // parse string input to integer and subtract // one in order to compare with rndNum // retrieve letter based on numeric input to // compare against rndGuess { uiInt = Integer.parseInt(uiStr) - 1; uiStr = Letters[uiInt]; } else { // if is isn't numeric pull first character // from user input into firstChar // then based on that store the numeric value // in uiInt for comparison with rndNum firstChar = uiStr.charAt(0); switch(firstChar) { case 'A': uiInt = 0; break; case 'B': uiInt = 1; break; case 'C': uiInt = 2; break; case 'D': uiInt = 3; break; case 'E': uiInt = 4; break; case 'F': uiInt = 5; break; case 'G': uiInt = 6; break; case 'H': uiInt = 7; break; case 'I': uiInt = 8; break; case 'J': uiInt = 9; break; default: JOptionPane.showMessageDialog(null, "Invalid Character Input", "Invalid Input", JOptionPane.INFORMATION_MESSAGE); done = true; break; } } if (uiInt < rndNum \| uiStr.compareTo(rndGuess) < 0) JOptionPane.showMessageDialog(null, "You're too low!", "Failure", JOptionPane.INFORMATION_MESSAGE); else if (uiInt > rndNum \| uiStr.compareTo(rndGuess) > 0) JOptionPane.showMessageDialog(null, "You're too high!", "Failure", JOptionPane.INFORMATION_MESSAGE); else JOptionPane.showMessageDialog(null, "Congratulations you guessed it", "Congratulations", JOptionPane.INFORMATION_MESSAGE); done = true; numGuesses++; } //end while if (numGuesses == 3) JOptionPane.showMessageDialog(null, "You lose, Too many Tries, Correct Letter = " + Letters[rndNum] + " and Correct Number = " + rndNum++, "Failure", JOptionPane.INFORMATION_MESSAGE); } } import java.util.; import javax.swing.JOptionPane; public class guessing2 { static Scanner console = new Scanner(System.in); private static boolean isNumeric(String checkStr) // determine if string is numeric { try{ Integer.parseInt(checkStr); return true; //Did not throw, must be a number }catch(NumberFormatException err){ return false; //Threw, So is not a number } } public static void main (String[] args) { int numGuesses = 0, uiInt = 0; boolean done = false; int rndNum = (int)(10.0 Math.random()); String uiStr = "", rndGuess = ""; char firstChar; String[] Letters = {"A", "B", "C", "D", "E", "F", "G", "H", "I", "J"}; rndGuess = Letters[rndNum]; while ((numGuesses < 3) && !done) { uiStr = JOptionPane.showInputDialog("Please enter a letter beween A-J or number between 1-10"); uiStr = uiStr.toUpperCase(); if(isNumeric(uiStr)) // check if user input was numeric // parse string input to integer and subtract // one in order to compare with rndNum // retrieve letter based on numeric input to // compare against rndGuess { uiInt = Integer.parseInt(uiStr) - 1; uiStr = Letters[uiInt]; } else { // if is isn't numeric pull first character // from user input into firstChar // then based on that store the numeric value // in uiInt for comparison with rndNum firstChar = uiStr.charAt(0); switch(firstChar) { case 'A': uiInt = 0; break; case 'B': uiInt = 1; break; case 'C': uiInt = 2; break; case 'D': uiInt = 3; break; case 'E': uiInt = 4; break; case 'F': uiInt = 5; break; case 'G': uiInt = 6; break; case 'H': uiInt = 7; break; case 'I': uiInt = 8; break; case 'J': uiInt = 9; break; default: JOptionPane.showMessageDialog(null, "Invalid Character Input", "Invalid Input", JOptionPane.INFORMATION_MESSAGE); done = true; break; } } if (uiInt < rndNum \| uiStr.compareTo(rndGuess) < 0) JOptionPane.showMessageDialog(null, "You're too low!", "Failure", JOptionPane.INFORMATION_MESSAGE); else if (uiInt > rndNum \| uiStr.compareTo(rndGuess) > 0) JOptionPane.showMessageDialog(null, "You're too high!", "Failure", JOptionPane.INFORMATION_MESSAGE); else JOptionPane.showMessageDialog(null, "Congratulations you guessed it", "Congratulations", JOptionPane.INFORMATION_MESSAGE); done = true; numGuesses++; } //end while if (numGuesses == 3) JOptionPane.showMessageDialog(null, "You lose, Too many Tries, Correct Letter = " + Letters[rndNum] + " and Correct Number = " + rndNum++, "Failure", JOptionPane.INFORMATION_MESSAGE); } } The reason I choose the Switch statement was mainly because I don't think that if a user inputs a letter that ".parseDouble" converts it to a numeric value. So my reasoning was that if they only guess letters they'll never succeed with that system. Please correct me if I'm wrong in that logic. -Manny http://www.leepoint.net/notes-java/a...andom-api.html http://bytes.com/forum/thread17584.html ---isNumeric() function http://www.roseindia.net/java/master...twise-or.shtml http://www.leepoint.net/notes-java/d...goverview.html http://www.javabeginner.com/java-string-comparison.htm http://forum.java.sun.com/thread.jsp...sageID=9698690 ---Converting letters to numbers http://java.sun.com/docs/books/tutor...ipstrings.html Last edited by manny85; Apr 12th, 2008 at 11:54 PM. Reason: Adjusting Code Format

Apr 13th, 2008, 12:55 AM	#9
manny85 Newbie Join Date: Apr 2008 Location: Ft Meade MD Posts: 6 Rep Power: 0	Re: Random "Letter" Generator Actually I don't think I made it very clear what I meant now that I reread my last post. I agree that using Double.parseDouble will convert a string, which contains a number (1-10 in our case), to an actual double. However if a string is storing a set a characters, in this case A-J, then I don't think Double.parseDouble will take that character and convert it to its/a numerical form. If it does in fact do that what values do the A-J end up being (numerically)...0-9, 1-10, ASCII values? Hope that makes more sense and also explains to kewlgeye why I choose the switch statement because I don't think his current program will respond correctly if a user inputs a character. Side note: Kewlgeye, are you trying to generate two separate random values meaning a random letter and a separate random number? In my code above I'm using the randomly generated number to retrieve the corresponding letter. So if a user inputs either the correct number or letter they win (1 or A, 2 or B, 3 or C, ... , 10 or J).

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Random "Letter" Generator