#include <iostream>

//function to calculate and return average with letter grade
void judgement(double grade1, double grade2, double grade3, double &average, char &letter)
{
    average = (grade1 + grade2 + grade3)/3;
    if (average <= 70)
        letter = 'P';
    else
        letter = 'F';
}

int main()
{
    double avg = 0.0;
    char result = 'N';
    judgement(58, 99, 45, avg, result);
    std::cout << avg << ": " << result << std::endl;
}