Run Length Encoding program

**Zora** · 03-09-2012, 06:23 AM

Hey guys,

So I'm working on a program which asks the user for a string of input (can be characters and numbers), and encodes the string like this:
Input: AAAABBBCD1223
Delimiter: *
Encodes: *4ABBBCD1223

If there are 3 or less of the same letters in a row, don't encode it. Don't encode numbers either. I don't know how or where to check the string that condition. Should I make another if statement or add it in an existing one?

Also, I have 2 errors that I don't know how to fix. I've tried indexOf, typingcasting it to char, nothing seems to work, but it seems like charAt makes the most sense here.

RunLengthEncoding.java:53: error: incompatible types
decoded = RLECode.charAt(i);
^
required: String
found: char
RunLengthEncoding.java:71: error: incompatible types
decoded = RLECode.charAt(i);
^
required: String
found: char

That's the first part of the program, ignore the printPicture method.

Here's my code:

Java Code:

import java.util.Scanner;
public class RunLengthEncoding
{
	public static void main (String[] args)
	{
		int w = 0;
		String runLengthCode;
		String decoded;
		String delim;
		Scanner input = new Scanner(System.in);
		System.out.print("Enter the width: ");
		if (input.hasNextInt())
		{
			w = input.nextInt();
			System.out.print("Enter the run-length code: ");
			runLengthCode = input.next();
			System.out.print("Enter a single character: ");
			delim = input.next();
			if (delim.length() == 1)
			{
				decoded = decodedRLE(runLengthCode, delim);
				printPicture(decoded, w);
			}
			else
				System.out.println("Invalid input. Only one character is allowed.");
		}
		else
			System.out.println("Invalid input. Only numbers are allowed.");
	}
	
	private static String decodedRLE(String RLECode, String delimiter)
	{
		int i = 0;
		int count = 1;
		String decoded = "";
		for (i = 0; i < RLECode.length();)
		{
			if(i + 1 < RLECode.length() && RLECode.charAt(i) == RLECode.charAt(i + 1))
			{
				if (RLECode.charAt(i) <= '9' && RLECode.charAt(i) >= '0')
				{
					count = 1;
					decoded = RLECode.charAt(i);
					i++;
				}
				else
				{
					while(i + 1 < RLECode.length() && RLECode.charAt(i) == RLECode.charAt(i + 1))
					{
						count++;
						i++;
					}
					decoded = delimiter + count + RLECode.charAt(i);
					i++;
					count = 1;
				}
			}
			else
			{
				count = 1;
				decoded = RLECode.charAt(i);
				i++;
			}
		}
		return decoded;
	}
	
	private static void printPicture(String decodedRLECode, int width)
	{
		System.out.print(decodedRLECode + " " + width);
	}
}