// This program uses an if/else if statement to assign a
// letter grade (A, B, C, D, or F) to a numeric test score.
#include <iostream>
using namespace std;

int main()
{
   int testScore;  // To hold a numeric test score
   char grade;     // To hold a letter grade

   // Get the numeric test score.
   cout << "Enter your numeric test score and I will\n";
   cout << "tell you the letter grade you earned: ";
   cin >> testScore;

   if (testScore < 0 || testScore > 100) //Input validation
   {
      // An invalid score was entered.
      cout << testScore << " is an invalid score.\n";
      cout << "Run the program again and enter a value\n";
      cout << "in the range of 0 to 100.\n";
   }
   else
   {
      // Determine the letter grade.
      if (testScore < 60)
         grade = 'F';
      else if (testScore < 70)
         grade = 'D';
      else if (testScore < 80)
         grade = 'C';
      else if (testScore < 90)
         grade = 'B';
      else if (testScore <= 100)
         grade = 'A';

      // Display the letter grade.
      cout << "Your grade is " << grade << endl;
   }
   return 0;
}