C++ ラベルとbreak文

#include <iostream>
using namespace std;

int main()
{
int n;
cout << "整数を入力せよ:";
cin >> n;

switch (n){
case 0: cout << "A";
cout << "B";
break;
case 2: cout << "C";
case 5: cout << "D";
break;
case 6:
case 7:cout << "E";
break;
default:cout << "F";
break;
}
cout << "\n";

return 0;
}