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Sep 20th, 2009

Change bases in Java

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First, I want to thank you for helping if you did, if not, thanks for checking it anyway. Second, I have been working on this for awhile, but I only am getting baby steps towards my goal. I get this far and I get compile correctly, but when I run it I get:
Exception in thread "main" java.lang.IllegalArgumentException: No enum const class project 2$Convert.bi
at java.lang.Enum.valueOf<Enum.java:196>
at project2$Convert.valueOf<project2.java:5>
at project2.main<project2.java:49>

Essentially, what I am trying to do is this: I have an input file has numbers like FFFFhex, 1010bin, 0013dec, 7777oct, and I want to convert it to decimal. I have to read these numbers one at a time and store them in a list. Then after they are all read and converted, I have to sort, print, and write the list into a new file.

Java Syntax (Toggle Plain Text)
import java.io.*;
import java.util.*;
public class project2
{
    public enum Convert { bin, oct, hex, dec}
    public static void main(String[] args)
    	                             throws IOException
    {
		//Declare variables
		String bin;
		String oct;
		String dec;
		String hex;
		String input;
		String output;
		String str;
 
                Scanner inFile = new Scanner(new  FileReader("E:\\LIFE.txt"));
		PrintWriter outFile = new PrintWriter("E:\\REPORT.txt");
 
		//Prompt
		System.out.println();
                System.out.println("Please be sure that the file LIFE is located in the root folder.");
		System.out.println("An example of this is C:");
		System.out.println("The REPORT file will be in the same location.");
 
 
 
 
		//Switch that will convert numbers
		while (inFile.hasNext())
{
		str = inFile.next();
 
		switch(Convert.valueOf(str.substring(4,6)))
		{
			case bin:
 
					int binary= Integer.parseInt(str,2);
			break;
			case oct:
 
    					int octal= Integer.parseInt(str,8);
			break;
			case hex:
 
    					int hexi= Integer.parseInt(str,16);
			break;
			case dec:
 
					str = str.substring(0,4);
			break;
			default: System.out.println("default");
		}
 
}
    }
}
import java.io.*;
import java.util.*;
public class project2
{
    public enum Convert { bin, oct, hex, dec}
    public static void main(String[] args)
    	                             throws IOException
    {
		//Declare variables
		String bin;
		String oct;
		String dec;
		String hex;
		String input;
		String output;
		String str;
		
                Scanner inFile = new Scanner(new  FileReader("E:\\LIFE.txt"));
		PrintWriter outFile = new PrintWriter("E:\\REPORT.txt");

		//Prompt
		System.out.println();
                System.out.println("Please be sure that the file LIFE is located in the root folder.");
		System.out.println("An example of this is C:");
		System.out.println("The REPORT file will be in the same location.");




		//Switch that will convert numbers
		while (inFile.hasNext())
{
		str = inFile.next();

		switch(Convert.valueOf(str.substring(4,6)))
		{
			case bin:

					int binary= Integer.parseInt(str,2);
			break;
			case oct:

    					int octal= Integer.parseInt(str,8);
			break;
			case hex:

    					int hexi= Integer.parseInt(str,16);
			break;
			case dec:

					str = str.substring(0,4);
			break;
			default: System.out.println("default");
		}

}
    }
}

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Hanyouslayer

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Sep 20th, 2009

Re: Change bases in Java

Looks like your input data has a value that is not one of your enum constants. Try printing str.substring(4,6) immediately before the switch.

JamesCherrill

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Sep 20th, 2009

Re: Change bases in Java

Read the contract of the substring method; substring(4, 6) == 2 characters.

Also get in the habit of using uppercase characters for enums i.e. `BIN' instead of `bin'.

Last edited by ~s.o.s~; Sep 20th, 2009 at 10:11 am.

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Sep 20th, 2009

Re: Change bases in Java

Due to some error, my account isn't activated as Hanyouslayer, so I made this one as a temp.

I changed my str.substring(4,6) to str.substring(4,7) (thanks to ~s.o.s~) because it was only taking in bi instead of bin. The first number on my list is 1010bin. When I put it outside the switch, it did return bin. Haha, there I go with lapse of attention to detail. I have solved the problem. The reason why it was having problems was because I wasn't being specific and it was reading the entire part, 1010bin, but I fixed it so it only reads 1010 when it converts.

ex of fixed code: This was for the binary conversion to decimal
int binary= Integer.parseInt(str.substring(0,4),2);

Thanks a lot guys for the help! I will flag this as solved when I get my account fixed.

Last edited by Dougnukem; Sep 20th, 2009 at 3:53 pm.

Dougnukem

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Sep 20th, 2009

Re: Change bases in Java

>Thanks a lot guys for the help!

Good luck with the remaining exercises.

> I will flag this as solved when I get my account fixed.

Done and done. :-)

~s.o.s~

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Sep 20th, 2009

Re: Change bases in Java

Well, I figured that part out, but I ran into something else that I have been trying to figure out all day. What I am having problems with now is inserting my converted numbers into my list. I have the list code down, but .add isn't working. I can only get it to take in the unconverted numbers. When I try and add my int binary in, it gives me cannot find symbol.
After this I surely wont need any help. I am fairly certain I can figure the rest out after this.
Thanks again.

Java Syntax (Toggle Plain Text)
import java.io.*;
import java.util.*;
 
 
public class project2
{
 
	public enum Convert { bin, oct, hex, dec}
    public static void main(String[] args)
    						 throws IOException
    {
		//Declare variables
		String str;
		int MAX = 12;
		int[] converted_list = new int[MAX];
 
		Scanner inFile = new Scanner(new FileReader("E:\\LIFE.txt"));
		PrintWriter outFile = new PrintWriter("E:\\REPORT.txt");
 
		//Prompt
		System.out.println();
        System.out.println("Please be sure that the file LIFE is located in the root folder.");
		System.out.println("An example of this is C:");
		System.out.println("The REPORT file will be in the same location.");
		System.out.println();
 
 
 
		//Switch that will convert numbers
		while (inFile.hasNext())
{
		str = inFile.next();
 
		switch(Convert.valueOf(str.substring(4,7)))
		{
			case bin:
 
						int binary= Integer.parseInt(str.substring(0,4),2);
 
 
			break;
			case oct:
 
    					int octal= Integer.parseInt(str.substring(0,4),8);
 
			break;
			case hex:
 
    					int hexi= Integer.parseInt(str.substring(0,4),16);
 
			break;
			case dec:
 
						str = str.substring(0,4);
 
			break;
			default: System.out.println("One of the numbers in the input file is incorrect. Ex. input 1010bin");
 
		}
 
		 //List for converted numbers
 
				List<String> ls=new ArrayList<String>();
		        ls.add(str.substring(0,4));
 
		        Iterator it=ls.iterator();
 
		        while(it.hasNext())
		        {
		          String value=(String)it.next();
 
		          System.out.println(str.substring(0,4));
 
}
}
 
   }
}
import java.io.*;
import java.util.*;


public class project2
{

	public enum Convert { bin, oct, hex, dec}
    public static void main(String[] args)
    						 throws IOException
    {
		//Declare variables
		String str;
		int MAX = 12;
		int[] converted_list = new int[MAX];

		Scanner inFile = new Scanner(new FileReader("E:\\LIFE.txt"));
		PrintWriter outFile = new PrintWriter("E:\\REPORT.txt");

		//Prompt
		System.out.println();
        System.out.println("Please be sure that the file LIFE is located in the root folder.");
		System.out.println("An example of this is C:");
		System.out.println("The REPORT file will be in the same location.");
		System.out.println();



		//Switch that will convert numbers
		while (inFile.hasNext())
{
		str = inFile.next();

		switch(Convert.valueOf(str.substring(4,7)))
		{
			case bin:

						int binary= Integer.parseInt(str.substring(0,4),2);


			break;
			case oct:

    					int octal= Integer.parseInt(str.substring(0,4),8);

			break;
			case hex:

    					int hexi= Integer.parseInt(str.substring(0,4),16);

			break;
			case dec:

						str = str.substring(0,4);

			break;
			default: System.out.println("One of the numbers in the input file is incorrect. Ex. input 1010bin");

		}

		 //List for converted numbers

				List<String> ls=new ArrayList<String>();
		        ls.add(str.substring(0,4));

		        Iterator it=ls.iterator();

		        while(it.hasNext())
		        {
		          String value=(String)it.next();

		          System.out.println(str.substring(0,4));

}
}

   }
}

Dougnukem

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Sep 21st, 2009

Re: Change bases in Java

COMPLETE!

Java Syntax (Toggle Plain Text)
import java.io.*;
import java.util.*;
 
 
public class project2
{
 
	public enum Convert { bin, oct, hex, dec}
    public static void main(String[] args)
    						 throws IOException
    {
		//Declare variables
		String str;
 
 
 
		Scanner inFile = new Scanner(new FileReader("E:\\LIFE.txt"));
		PrintWriter outFile = new PrintWriter("E:\\REPORT.txt");
 
		//Prompt
		System.out.println();
        System.out.println("Please be sure that the file LIFE is located in the root folder.");
		System.out.println("An example of this is C:");
		System.out.println("The REPORT file will be in the same location.");
		System.out.println();
 
List<Integer> ls = new ArrayList<Integer>();
 
		//Switch that will convert numbers
		while (inFile.hasNext())
{
		str = inFile.next();
 
		switch(Convert.valueOf(str.substring(4,7)))
		{
			case bin:
 
						int binary= Integer.parseInt(str.substring(0,4),2);
							ls.add(binary);
			break;
			case oct:
 
    					int octal= Integer.parseInt(str.substring(0,4),8);
							ls.add(octal);
			break;
			case hex:
 
    					int hexi= Integer.parseInt(str.substring(0,4),16);
							ls.add(hexi);
			break;
			case dec:
						int deci= Integer.parseInt(str.substring(0,4),10);
							ls.add(deci);
			break;
			default: System.out.println("One of the numbers in the input file is incorrect. Ex. input 1010bin");
		}
}
			//Output unsorted
			System.out.println("Unsorted");
			System.out.println(ls);
 
			//Output unsorted to file
			outFile.println("Unsorted");
			outFile.print(ls);
			outFile.println("");
			outFile.println("Sorted");
 
			//Sort
			Collections.sort(ls);
 
			//Output sorted
			System.out.println("Sorted");
			System.out.println(ls);
 
			//Output sorted to file
			outFile.print(ls);
 
			//Close files
			inFile.close();
			outFile.close();
   }
}
import java.io.*;
import java.util.*;


public class project2
{

	public enum Convert { bin, oct, hex, dec}
    public static void main(String[] args)
    						 throws IOException
    {
		//Declare variables
		String str;



		Scanner inFile = new Scanner(new FileReader("E:\\LIFE.txt"));
		PrintWriter outFile = new PrintWriter("E:\\REPORT.txt");

		//Prompt
		System.out.println();
        System.out.println("Please be sure that the file LIFE is located in the root folder.");
		System.out.println("An example of this is C:");
		System.out.println("The REPORT file will be in the same location.");
		System.out.println();

List<Integer> ls = new ArrayList<Integer>();

		//Switch that will convert numbers
		while (inFile.hasNext())
{
		str = inFile.next();

		switch(Convert.valueOf(str.substring(4,7)))
		{
			case bin:

						int binary= Integer.parseInt(str.substring(0,4),2);
							ls.add(binary);
			break;
			case oct:

    					int octal= Integer.parseInt(str.substring(0,4),8);
							ls.add(octal);
			break;
			case hex:

    					int hexi= Integer.parseInt(str.substring(0,4),16);
							ls.add(hexi);
			break;
			case dec:
						int deci= Integer.parseInt(str.substring(0,4),10);
							ls.add(deci);
			break;
			default: System.out.println("One of the numbers in the input file is incorrect. Ex. input 1010bin");
		}
}
			//Output unsorted
			System.out.println("Unsorted");
			System.out.println(ls);

			//Output unsorted to file
			outFile.println("Unsorted");
			outFile.print(ls);
			outFile.println("");
			outFile.println("Sorted");

			//Sort
			Collections.sort(ls);

			//Output sorted
			System.out.println("Sorted");
			System.out.println(ls);

			//Output sorted to file
			outFile.print(ls);

			//Close files
			inFile.close();
			outFile.close();
   }
}

Dougnukem

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Sep 21st, 2009

Re: Change bases in Java

A few observations:
- Always perform resource cleanup in the `finally' block to be rest assured that the cleanup indeed is performed even if the code ends up throwing an exception.
- The way you have written your code resembles the procedural ad-hoc way of writing code. Break up your logic in methods and create logical classes which represent your problem domain.

Taking a look at the sticky created at the top of the forum might just help you get started in the right direction.

~s.o.s~

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Sep 21st, 2009

Re: Change bases in Java

I was going to make two classes and a few methods, maybe about 6, and in order to break it up into classes, I went with a driver and a worker class. Upon doing it it came up with errors when compiling, however, if I run it it will work fine. I get 15 errors in total:
.\converter.java:3: cannot find symbol
symbol : class Scanner
location: class converter
static Scanner console = new Scanner(System.in);
^
.\converter.java:3: cannot find symbol
symbol : class Scanner
location: class converter
static Scanner console = new Scanner(System.in);
^
.\converter.java:14: cannot find symbol
symbol : class Scanner
location: class converter
Scanner inFile = new Scanner(new FileReader(infile));
^
.\converter.java:14: cannot find symbol
symbol : class Scanner
location: class converter
Scanner inFile = new Scanner(new FileReader(infile));
^
.\converter.java:14: cannot find symbol
symbol : class FileReader
location: class converter
Scanner inFile = new Scanner(new FileReader(infile));
^
.\converter.java:15: cannot find symbol
symbol : class PrintWriter
location: class converter
PrintWriter outFile = new PrintWriter(outfile);
^
.\converter.java:15: cannot find symbol
symbol : class PrintWriter
location: class converter
PrintWriter outFile = new PrintWriter(outfile);
^
.\converter.java:25: cannot find symbol
symbol : class List
location: class converter
List<Integer> ls = new ArrayList<Integer>();
^
.\converter.java:25: cannot find symbol
symbol : class ArrayList
location: class converter
List<Integer> ls = new ArrayList<Integer>();
^
.\converter.java:32: cannot find symbol
symbol : variable Convert
location: class converter
switch(Convert.valueOf(str.substring(4,7)))
^
.\converter.java:34: cannot find symbol
symbol : variable bin
location: class converter
case bin:
^
.\converter.java:39: cannot find symbol
symbol : variable oct
location: class converter
case oct:
^
.\converter.java:44: cannot find symbol
symbol : variable hex
location: class converter
case hex:
^
.\converter.java:49: cannot find symbol
symbol : variable dec
location: class converter
case dec:
^
.\converter.java:71: cannot find symbol
symbol : variable Collections
location: class converter
Collections.sort(ls);

My driver method:

Java Syntax (Toggle Plain Text)
import java.io.*;
import java.util.*;
 
public class project2
{
 
    public static void main(String[] args)
    						 throws IOException  {
 
		converter convertObject = new converter();
		convertObject.converting();
 
   }
}
import java.io.*;
import java.util.*;

public class project2
{

    public static void main(String[] args)
    						 throws IOException  {

		converter convertObject = new converter();
		convertObject.converting();

   }
}

And my worker:

Java Syntax (Toggle Plain Text)
public class converter
{
	static Scanner console = new Scanner(System.in);
    public void converting()
    {
		//Declare variables
		String str;
		String infile;
		String outfile;
 
		//Get file locations
		System.out.println("Enter location of the input file.");
		System.out.println("An example of this is C:");
		infile = console.next();
		System.out.println("Enter location of the input file.");
		outfile = console.next();
		Scanner inFile = new Scanner(new FileReader(infile));
		PrintWriter outFile = new PrintWriter(outfile);
 
	        //Create list
		List<Integer> ls = new ArrayList<Integer>();
 
		//Switch that will convert numbers
		while (inFile.hasNext())
		{
		str = inFile.next();
 
		switch(Convert.valueOf(str.substring(4,7)))
		{
		case bin:
		int binary= Integer.parseInt(str.substring(0,4),2);
				ls.add(binary);
		break;
 
		case oct:
			int octal= Integer.parseInt(str.substring(0,4),8);
		    	ls.add(octal);
		break;
 
		case hex:
		    int hexi= Integer.parseInt(str.substring(0,4),16);
		      	ls.add(hexi);
		break;
 
		case dec:
		    int deci= Integer.parseInt(str.substring(0,4),10);
				ls.add(deci);
		break;
 
		default: System.out.println("One of the numbers in the input file is incorrect. Ex. input 1010bin");
		}
 
		}
 
		//Output unsorted
		System.out.println("Unsorted");
		System.out.println(ls);
 
 
		//Output unsorted to file
		outFile.println("Unsorted");
		outFile.print(ls);
		outFile.println("");
		outFile.println("Sorted");
 
		//Sort
		Collections.sort(ls);
 
 
 
		//Output sorted
		System.out.println("Sorted");
		System.out.println(ls);
 
		//Output sorted to file
		outFile.print(ls);
 
 
 
		//Close files
		inFile.close();
		outFile.close();
 
	}
 
}
public class converter
{
	static Scanner console = new Scanner(System.in);
    public void converting()
    {
		//Declare variables
		String str;
		String infile;
		String outfile;

		//Get file locations
		System.out.println("Enter location of the input file.");
		System.out.println("An example of this is C:");
		infile = console.next();
		System.out.println("Enter location of the input file.");
		outfile = console.next();
		Scanner inFile = new Scanner(new FileReader(infile));
		PrintWriter outFile = new PrintWriter(outfile);

	        //Create list
		List<Integer> ls = new ArrayList<Integer>();

		//Switch that will convert numbers
		while (inFile.hasNext())
		{
		str = inFile.next();

		switch(Convert.valueOf(str.substring(4,7)))
		{
		case bin:
		int binary= Integer.parseInt(str.substring(0,4),2);
				ls.add(binary);
		break;

		case oct:
			int octal= Integer.parseInt(str.substring(0,4),8);
		    	ls.add(octal);
		break;

		case hex:
		    int hexi= Integer.parseInt(str.substring(0,4),16);
		      	ls.add(hexi);
		break;

		case dec:
		    int deci= Integer.parseInt(str.substring(0,4),10);
				ls.add(deci);
		break;

		default: System.out.println("One of the numbers in the input file is incorrect. Ex. input 1010bin");
		}

		}

		//Output unsorted
		System.out.println("Unsorted");
		System.out.println(ls);


		//Output unsorted to file
		outFile.println("Unsorted");
		outFile.print(ls);
		outFile.println("");
		outFile.println("Sorted");

		//Sort
		Collections.sort(ls);



		//Output sorted
		System.out.println("Sorted");
		System.out.println(ls);

		//Output sorted to file
		outFile.print(ls);



		//Close files
		inFile.close();
		outFile.close();

	}

}

Last edited by Dougnukem; Sep 21st, 2009 at 3:01 am.

Dougnukem

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Sep 21st, 2009

Re: Change bases in Java

Your second file is missing the class imports. I don't see the declaration of your `Convert' enum class. Your naming conventions are still off.

These are pretty simple error messages to hunt down and fix; I'd recommend reading the sticky at the top of the forum.

Last edited by ~s.o.s~; Sep 21st, 2009 at 10:05 am.

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