Trouble with charAt and nested for loops

Question

Hi,
I have a programming assignment in which my goal is to write a program that reads a social security number written as contiguous digits (eg, 509435456; obtained via JOptionPane); uses charAt to obtain each character; and then prints each digit on a separate line, followed by a colon and the digit printed the number of times equal to its value. Thus the output for 509435456 would be:
5:55555
0:
9:999999999
4:4444
3:333
5:55555
4:4444
5:55555
6:666666
I'm also required to use a char variable for the inner loop control variable, and write the inner for loop as something along the lines of
for(char index = '1'; index <= digit; index++) where digit is the char variable use to store the digit taken from the string.
Here's what I have so far:
import javax.swing.JOptionPane;
public class Prog3a
     public static void main (String [] asd)
     String ssn = JOptionPane.showInputDialog("Que es tu SSN?");
     for (int rows = 0; rows < 9; rows++) //number of rows
               char digit = ssn.charAt(rows) - '0';
               System.out.print(digit + ":");
               for (char index = 0; index < digit; index ++) //how many characters are going to be on each row
                         System.out.print(digit);
          System.out.println("");
}Unfortunately, the char digit = ssn.charAt(rows) - '0'; errors on me, and only works when char is replaced with int. However, digit is no longer a char for the inner loop, and this fails to meet the requirements of the assignment. How can I assign the char without this "loss of precision"?

Answer 1

Original Assignment:
+3a. Write a program that reads a social security number written as contiguous digits (for instance, 509435456), uses the charAt method to obtain each character and then prints each digit on a separate line followed by a colon and the digit printed the number of times equal to its value. Thus the output for 509435456 would be+
+5:55555+
+0:+
+9:999999999+
+4:4444+
+3:333+
+5:55555+
+4:4444+
+5:55555+
+6:666666+
The string should be read using JOptopnPane.
+Use a char variable, e.g., index, for the inner loop control variable and write the inner for loop as for(char index = '1'; index <= digit; index++) where digit is the char variable use to store the digit taken from the string.+
+3b. Write the program so that index, the inner loop index, is an int variable. This means you must convert the character assigned to digit to an int.+
Is that any help? It's as much as I know.