C / C++: switch .. case

Вывод времени года по месяцу:

#include <stdio.h>
#include <iostream>
    using namespace std;
int main () {
int a;
    cin >> a;
switch (a) {
    case 12: cout << "zima";  break;
    case  1: cout << "zima";  break;
    case  2: cout << "zima";  break;
    case  3: cout << "vesna"; break;
    case  4: cout << "vesna"; break;
    case  5: cout << "vesna"; break;
    case  6: cout << "leto";  break;
    case  7: cout << "leto";  break;
    case  8: cout << "leto";  break;
    case  9: cout << "osen";  break;
    case 10: cout << "osen";  break;
    case 11: cout << "osen";  break;
    default: cout << "osen";  break;}
}