/*
 This application demonstrate various control structures and additional
	I/O methods
*/

import java.io.*;

public class GradeAverage
{
   public static void main (String args[]) throws IOException
   {
      // declaring a constant variable
      final int NUM = 5;

      char lettergrade;
      int total = 0;
      int counter = 1;
      double average;

      // while loop and if tests
      while (counter <= NUM)
      { System.out.print("Enter letter grade: " );
	// read a byte from standard input and convert to a char
	lettergrade = (char)System.in.read();
	if (lettergrade == 'A')
	   total += 4;
	else if (lettergrade == 'B')
	   total += 3;
	else if (lettergrade == 'C')
	   total += 2;
	else if (lettergrade == 'D')
	   total += 1;
	
	// skips one byte (the return) of standard input
	System.in.skip (1);
	counter ++;
      }

      // cast to get floating point arithmetic
      average = (double) total/NUM;
      System.out.println ("Class average is " + average );
   }
}