#include <iostream>
using namespace std;
const float cutoff = 7.0;
char grade( int exam1, int exam2, float exam_weight );

int main() {
   int mid_term, final;
   float weight;
   char ans, letter_grade;

   do {
      cout << "\n\nCompute another grade (Y)es, (N)o? ";
      cin >> ans;
      if ( ans == 'Y' ) {
         cout << "Enter mid term, final, weight: ";
         cin >> mid_term >> final >> weight;
         letter_grade = grade( mid_term, final, weight );
         cout << "Grade is: " << letter_grade << endl;
      }
   } while ( ans == 'Y');
   return 0;
}

char grade( int exam1, int exam2, float exam1_weight ) {
   float average;
   average = exam1_weight * exam1 
             + ( 1.0 - exam1_weight ) * exam2;
   if ( average > cutoff )
      return 'P';
   else
      return 'F';
}