int score;
cout << "점수를 입력하세요.";
cin >> score;
if (score >= 90) {
cout << "A학점" << endl;
}
else if ((score >= 80) && (score < 90)) {
cout << "B학점" << endl;
}
else if ((score >= 70) && (score < 80)) {
cout << "C학점" << endl;
}
else if ((score >= 60) && (score < 70)) {
cout << "D학점" << endl;
}
else {
cout << "F학점" << endl;
}
if문