// gpa.cpp

#include <iostream>
#include <fstream>
using namespace std;

int main(int argc, char** argv)
{
   char grade;
   cout << "Enter grade:> ";
   cin >> grade;

   int points;
   switch ( grade )
   {
      case 'A': case 'a':       points = 4;        break;
      case 'B': case 'b':       points = 3;        break;
      case 'C': case 'c':       points = 2;        break;
      case 'D': case 'd':       points = 1;        break;
      case 'F': case 'f':       points = 0;        break;

      default:                  points = -1;   // to indicate not valid
   }  // switch

   if ( points == -1 )   // i.e. if grade was not valid
      cout << "Error: " << grade
               << " not a valid grade." << endl;
   else
      cout << "Grade points = " << points << endl;

   return 0;
}  // function main