Help with String Buffer

[mathias]

Hello, I have been given a few sample test questions, and one of them is as follows.

Write a method that counts the occurrences of each digit in a string using the following header:

Code:

public static int[] count (String s)

The method counts how many times a digit appears in the string. The return value is an array of ten elements each of which holds the counts for a digit.

I have done one with said criteria for Strings to count occurrences of characters, but for a combination, I am trying to figure out how to clean out the characters and leave just the integers.

I used the following in an attempt:

Code:

import javax.swing.JOptionPane;
public class mainCount {
public static void main(String[] args) {

String s = JOptionPane.showInputDialog(null, "Enter a string with numbers: ", "Test Q 7-5", JOptionPane.QUESTION_MESSAGE);

String s1 = filter(s);
}
public static String filter(String s) {
StringBuffer strBuf = new StringBuffer();

for(int i = 0; i < s.length(); i++) {
if(Character.isDigit(s.charAt(i))) {
strBuf.append(s.charAt(i));
}

return strBuf.toString();
}
}
}

I keep getting an error that the method (filter) must return a String type.
From what I have learnt isn't it doing just that, having the numbers of the entered string back as a string.

It would be greatly appreciated if anyone could help me.

Thanks.

[baltimore]

You are getting a compiler error are because you have placed the return statement inside the for loop. It isn't grammatically incorrect to have a return statement inside a for loop (as long as it makes sense to have it there)...but you need to have a return statement after the for loop regardless.
try writing it this way

Code:

import javax.swing.JOptionPane;
public class mainCount {
public static void main(String[] args) {

String s = JOptionPane.showInputDialog(null, "Enter a string with numbers: ", "Test Q 7-5", JOptionPane.QUESTION_MESSAGE);

String s1 = filter(s);
}
public static String filter(String s) {
StringBuffer strBuf = new StringBuffer();

for(int i = 0; i < s.length(); i++) {
if(Character.isDigit(s.charAt(i))) {
strBuf.append(s.charAt(i));
}

//return strBuf.toString();
} // for loop ends here
return strBuf.toString();
} //--filter method ends here.
}

Hope that helps