// Counting letter grades
#include <iostream.h>

main()
{
   int grade;
   int aCount = 0, bCount = 0, cCount = 0,
       dCount = 0, fCount = 0;

   cout << "Enter the letter grades." << endl
        << "Enter the EOF character to end input." << endl;

   while ( ( grade = cin.get() ) != EOF ) {

      switch (grade) {        // switch nested in while

         case 'A': case 'a':  // Grade was uppercase A
            ++aCount;         // or lowercase a.
            break;

         case 'B': case 'b':  // Grade was uppercase B
            ++bCount;         // or lowercase b.
            break;

         case 'C': case 'c':  // Grade was uppercase C
            ++cCount;         // or lowercase c.
            break;

         case 'D': case 'd':  // Grade was uppercase D
            ++dCount;         // or lowercase d.
            break;

         case 'F': case 'f':  // Grade was uppercase F
            ++fCount;         // or lowercase f.
            break;

         case '\n': case ' ':  // ignore these in input
            break;

         default:             // catch all other characters
            cout << "Incorrect letter grade entered."
                 << " Enter a new grade." << endl;
            break;
      }
   }

   cout << endl << "Totals for each letter grade are:" 
        << endl << "A: " << aCount << endl << "B: " << bCount
        << endl << "C: " << cCount << endl << "D: " << dCount
        << endl << "F: " << fCount << endl;

   return 0;
}