First, please use proper English (i.e. not "plz") when posting on Daniweb.
I would use an std::map. Traverse the string a character at a time. If the element doesn't exist in the map, add it to the map as a key with value=1. If it does already exist in the map, increment the associated value.
public class GrossmontBank
//class variables (global - accessible throughout this class)
//scanner object to be used throughout
private static Scanner input = new Scanner(System.in);