/* Filename:  grade3.cpp

   Author:  Br. David Carlson
            Br. Isidore Minerd

   Date:  January 4, 2000

   Modified:  June 26, 2000; August 19, 2001; July 16, 2009

   This program asks the user to enter number grades between 0 and 100.
   It computes and prints the corresponding letter grade (A, B, C,
   D, or F) for each.  The user is told to enter a fake grade of -1
   to stop the program.

   Tested with:
      Microsoft Visual C++ 6.0
      Microsoft Visual C++ .NET
      Microsoft Visual Studio 2008
      g++ under Linux
*/

#include <iostream>
using namespace std;


// Function prototype:

char ConvertGrade(int Num);


int main(void)
   {
   int NumberGrade;
   char LetterGrade;

   cout << "Enter your number grade (integer from 0 to 100, -1 to quit): ";
   cin >> NumberGrade;
   cin.get();

   while (NumberGrade != -1)
      {
      LetterGrade = ConvertGrade(NumberGrade);
      cout << endl << "The letter grade is: " << LetterGrade << endl << endl;

      cout << "Enter your number grade (integer from 0 to 100, -1 to quit): ";
      cin >> NumberGrade;
      cin.get();
      }

   return 0;
   }


/* Given:  Num      An integer from 0 to 100.
   Task:   To convert Num to a letter grade.
   Return: This letter grade in the function name.
*/
char ConvertGrade(int Num)
   {
   char Grade;

   if ((Num < 0) || (Num > 100))
      Grade = 'N';
   else if (Num >= 90)
      Grade = 'A';
   else if (Num >= 80)
      Grade = 'B';
   else if (Num >= 70)
      Grade = 'C';
   else if (Num >= 60)
      Grade = 'D';
   else
      Grade = 'F';

   return Grade;
   }