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).

titaniumdecoy · Apr 13th, 2008, 1:00 AM

Double.parseDouble will throw a NumberFormatException if it is unable to parse its input as a double. It is very easy to find this information in the docs.

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).

Apr 13th, 2008, 1:00 AM	#10
titaniumdecoy Expert Programmer Join Date: Nov 2005 Posts: 837 Rep Power: 3	Re: Random "Letter" Generator Double.parseDouble will throw a NumberFormatException if it is unable to parse its input as a double. It is very easy to find this information in the docs.

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Random "Letter" Generator