9498: 시험성적

https://www.acmicpc.net/problem/9498

#include <iostream>
#include <string>

using namespace std;

int main(){
    int score;
    cin >> score;
    switch (score/10)
    {
    case 10:
    case 9:
        cout << 'A';
        break;
    case 8:
        cout << 'B';
        break;
    case 7:
        cout << 'C';
        break;
    case 6:
        cout << 'D';
        break;
    default:
        cout << 'F';
        break;
    }
    
    return 0;
}