#include <iostream> using namespace std; char gradeFunction(double avg) { if (avg >= 90) return 'A'; else if (avg >= 80) return 'B'; else if (avg >= 70) return 'C'; else if (avg >= 60) return 'D'; else return 'F'; } int main() { int count; double sum = 0, grade; cout << "How many grades (1 to 5)? "; cin >> count; if (count < 1 || count > 5) { cout << "Invalid number. You must enter between 1 and 5 grades.\n"; return 1; } for (int i = 1; i <= count; i++) { cout << "Enter grade " << i << ": "; cin >> grade; sum += grade; } double avg = sum / count; cout << "Average: " << avg << "\n"; cout << "Letter grade: " << gradeFunction(avg) << "\n"; return 0; }