How to find string range

Question

Say i have a string array from aa0 to aa100. Now how do i write a condition to check that this string lies between aa0 to aa100. please help

Answer 1

This is the code what i have typed. Its working but when i enter a value which is less then 0 and greater than 99, it still works, where as it shouldnt. Please help
    public void focusLost(FocusEvent evt) {
                if(evt.getSource() == mytextfield) {
              System.out.println("Inside focuslost");
              String text = mytextfield.getText();
              if(text.startsWith("aa")) {
                   int value;
                   try {
                        value = Integer.parseInt(String.valueOf(text.charAt(text.length() - 1)));
                   }catch(NumberFormatException nfe) {JOptionPane.showMessageDialog(null,"textfield should be \n in the range of aa0 - aa99","Test",JOptionPane.ERROR_MESSAGE);return;}
                   if(value < 0 || value > 99) {
                        System.out.println("Inside if condition");
                        JOptionPane.showMessageDialog(null,"textfield should be \n in the range of aa0 - aa99","Test",JOptionPane.ERROR_MESSAGE);
                        mytextfield.transferFocus();
                        return;
              else {
                    JOptionPane.showMessageDialog(null,"Invalid entry","Test",JOptionPane.ERROR_MESSAGE);
                    return;
    }