title: How to increase charAt value inside a while loop
body: <p>I'm trying to find a way to increase a value that is using charAt, but want to be able to update it while inside a while loop. Below is the current code that I have. I have tried recreating the variable inside of the loop and adding ++ to the end to increase the value, but I receive unexpected type errors.</p>
  
  <p>I am trying to have it take a value that you enter (i.e. 3124) and concatenate each value and then add them together. So based on the example, it would give a value of 10.</p>
  
  <pre><code>public static void main(String[] args) {
  
  int Num, counter, i;
  String str1;
  
  
  str1 = JOptionPane.showInputDialog("Enter any number: ");
  Num = str1.length();
  
  counter = 0;
  i = Integer.parseInt(Character.toString(str1.charAt(0)));
  NumTot = 0;
  
  while (counter &lt;= Num)
  {
    NumTot = i;
    counter++;
    i = Integer.parseInt(Character.toString(str1.charAt(0++)));
    }
  
       System.exit(0);
  }
  </code></pre>