Stepan

#include <iostream>
#include<math.h>
#include<vector>
#include<string>
using namespace std;
template <typename q>
ostream& operator << (ostream& out, vector<q>& temp) {
    for (auto& s : temp) {
        cout << s << ' ';
    }
    cout << endl;
    return out;
}

class desktop
{
public:
    void on() {
        cout << "power on\n";
    }
    void off() {
        cout << "power off\n";
    }
    void blocknot() {
        vector<string> temp;
        string tmp;
        cout << "enter your text\n";
        cin >> tmp;
        temp.push_back(tmp);
        cout << temp;
    }
    void calc() {
        int a, b;
        cin >> a >> b;
        cout << a + b<<'\n';
    }
    void koren() {
        int i;
        cout << "vvedite chislo" << endl;
        cin >> i;
        cout << sqrt(i);

    }
};


class Facade
{
public:

    desktop cur;
    void operation() {
        cout << "0-vkluchit\n 1 - calc\n 2 - koren\n 3 - blocknot\n 4 - vuklychit\n";
        int s;
        cin >> s;
        switch (s) {
        case 0:
            cur.on();
            break;
        case 1:
            cur.calc();
            break;
        case 2:
            cur.koren();
            break;
        case 3:
            cur.blocknot();
            break;
        case 4:
            cur.off();
            break;
        }
    }

};

int main()
{
    while (1) {
        Facade PC;
        PC.operation();
    }


}