C++ :

#include <iostream>
using namespace std;
int main() {
    int num;
    cin >> num;
    switch (num > 0) {
        case true:
            switch (num % 2) {
                case 0: cout << "正偶数"; break;
                case 1: cout << "正奇数"; break;
            }
            break;
        case false:
            switch (num < 0) {
                case true:
                    switch (-num % 2) {
                        case 0: cout << "负偶数"; break;
                        case 1: cout << "负奇数"; break;
                    }
                    break;
                case false: cout << "零是偶数"; break;
            }
            break;
    }
    return 0;
}