Problem 1. (Average GPA) Write an ST client called AvgGPA that creates a symbol table mapping letter grades to numerical scores, as in the table below, then reads from standard input a list of letter grades and computes and prints the average GPA (the average of the numbers corresponding to the grades).

$ java AvgGPA B A - A A - B A - A - B A+ B A + A - B - B B+ B+ A C A + F 3.2835

import edu.princeton.cs.algs4.StdIn; import edu.princeton.cs.algs4.StdOut; import edu.princeton.cs.algs4.ST;

public class AvgGPA { public static void main(String[] args) { ... }