Help with a task.

[checho]

I have the next task. My problem comes when i want to replace the words with '*', iam counting how many * i need in a loop, but when i try to replace them it says that the variable charz is unresolveble:

public class Zadacha_6 {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		/*
* We are given a string containing a list of forbidden 
* words and a text containing some
of these words. Write a program that replaces the forbidden
 words with asterisks.
Example: Words: "Java, JVM, Microsoft"
The expected result: Microsoft announced its next generation Java
compiler today. It uses advanced parser and special optimizer 
for the Microsoft JVM.
********* announced its next generation **** compiler today. 
*It uses advanced parser and
special optimizer for the ********* ***.
		 */
		String text = "Microsoft announced its next generation Java" +
				" compiler today. It uses advanced parser and " +
				"special optimizer for the Microsoft JVM. ";
		String forbiddenWords = "Java, JVM, Microsoft";
		String[] arr = forbiddenWords.split("[ ,]+");
		StringBuilder str = new StringBuilder();
		str.append(text);
		String newString = null;
		for (String word : arr){
			System.out.println (word);
			int lenght = word.length();
			int index = text.indexOf(word);
			
			for (int i = 0; i <word.length(); i++){
				
				StringBuilder charz = new StringBuilder();
				 charz.append('*');
				 System.out.print(charz);
			}
						
			newString = text.replaceAll(word, charz);
			System.out.println (newString);
	
		}
	
	}

}

[Fubarable]

To simplify, you have this:

      for (int i = 0; i < word.length(); i++) {
        StringBuilder charz = new StringBuilder(); // *** charz declared here in for loop
        charz.append('*');
        System.out.print(charz);
      }

      newString = text.replaceAll(word, charz);

You declare charz within the for loop, and so it is visible only within that for loop. Once your code steps out of the loop, *poof*, charz is gone. Solution, declare it before the loop.

You have another problem too in that charz is a StringBuilder object, and you appear to be trying to use it like a String in the replaceAll method.

[[RaIdEn]]

just make charz as a string, declare it outside the loop and play with it.

It should be pretty easy from then

[checho]

Here i came to this point but its not working correctly? Can someone tell me why?

public class Zadacha_6 {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		/*
* We are given a string containing a list of forbidden 
* words and a text containing some
of these words. Write a program that replaces the forbidden
 words with asterisks.
Example: Words: "Java, JVM, Microsoft"
The expected result: Microsoft announced its next generation Java
compiler today. It uses advanced parser and special optimizer 
for the Microsoft JVM.
********* announced its next generation **** compiler today. 
*It uses advanced parser and
special optimizer for the ********* ***.
		 */
		String text = "Microsoft announced its next generation Java" +
				" compiler today. It uses advanced parser and " +
				"special optimizer for the Microsoft JVM. ";
		String forbiddenWords = "Java, JVM, Microsoft";
		String[] arr = forbiddenWords.split("[ ,]+");
	
		String newString = null;
		
		for (String word : arr){
			int lenght = word.length();
				String chars = "";
			for (int i = 0; i <word.length(); i++){
				chars += '*';
			}
			newString = text.replaceAll(word, chars);
			
		}
		System.out.println (newString);
	}

}

The result it:
**************** announced its next generation Java compiler today. It uses advanced parser and special optimizer for the **************** JVM.


java isnt replaced
jvm too

[dlorde]

The replacement is working OK, but you're going back to the original text each time, so the previous replacement is lost. You end up with only the last replacement.

Incidentally, you should be using StringBuilder whenever you concatenate text or characters inside a loop - it's much more efficient. You can convert back to a String whenever you need to using the toString() method. Alternatively, you could forget the loop and just grab the number of '*' you need from a predefined string of them, using subString(..).

[checho]

Solved. Here is the working code in case someone needs it.
Thanks for the help.

public class Zadacha_6 {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		//raboti
		/*
* We are given a string containing a list of forbidden 
* words and a text containing some
of these words. Write a program that replaces the forbidden
 words with asterisks.
Example: Words: "Java, JVM, Microsoft"
The expected result: Microsoft announced its next generation Java
compiler today. It uses advanced parser and special optimizer 
for the Microsoft JVM.
********* announced its next generation **** compiler today. 
*It uses advanced parser and
special optimizer for the ********* ***.
		 */
		String text = "Microsoft announced its next generation Java" +
				" compiler today. It uses advanced parser and " +
				"special optimizer for the Microsoft JVM. ";
		String forbiddenWords = "Java, JVM, Microsoft";
		String[] arr = forbiddenWords.split("[ ,]+");
		String newString = "";
		
		StringBuilder sb = new StringBuilder();
		sb.append(text);
		
		
		for (String word : arr){
			int lenght = word.length();
			int index = sb.indexOf(word);
			String chars = "";
				for (int i = 0; i <word.length(); i++){
					chars += '*';
				}
					while (index != -1){
					
						sb.delete(index, index+lenght);
						sb.insert(index, chars);
						index = sb.indexOf(word);
					}
			
			
		}
		System.out.println (sb.toString());
	}

}