ex5_6.cpp

#include <iostream>
#include <vector>
#include <string>
using std::vector; using std::string; using std::cout; using std::endl; using std::cin;

int main()
{
    vector<string> scores = { "F", "D", "C", "B", "A", "A++" };

    int grade = 0;
    while (cin >> grade)
    {
        string lettergrade = grade < 60 ? scores[0] : scores[(grade - 50) / 10];
        lettergrade += (grade == 100 || grade < 60) ? "" : (grade % 10 > 7) ? "+" : (grade % 10 < 3) ? "-" : "";
        cout << lettergrade << endl;
    }

    return 0;
}