站长！！，room！！，我为什么80分？

#include #include #include #include #include using namespace std;

int main() { int n; while (cin >> n) { if (n>=90&&n<=100) { cout << "A" << endl; } else if (n>=80&&n<=89) { cout << "B" << endl; } else if (n >= 70 &&n <= 79) { cout << "C" << endl; } else if (n >= 60 &&n <= 69) { cout << "D" << endl; } else if (n>=0&&n<=59) { cout << "E" << endl; } } return 0; }