Duty list

#include <algorithm>
#include <iostream>
#include <string>
#include <vector>
#include <ctime>

int pref_months[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; // Days in month

std::vector<std::string> list ={
        "Anisevich Egor",
        "Ardytskaya Karina",
        "Basik Denis",
        "Bychkovski Roman",
        "Evtikhov Artyom",
        "Karpuk Maksim",
        "Koliada Ilya",
        "Kuchinski Ilya",
        "Luksha Maria",
        "Parkhomenko Sasha",
        "Petlyova Sasha",
        "Polyakov Roman",
        "Prokopenia Karina",
        "Saevets Sofia",
        "Savcuk Emma",
        "Shepel Katia",
        "Shimanskaya Efrosinia",
        "Silenkova Dasha",
        "Stepanuk Kirill",
        "Zhuk Ksenia"
}; // Main list of the klass

int32_t main() {
    /*std::ifstream fin("klass.txt");
    std::string now;
    while(std::getline(fin, now))
        list.push_back(now);*/ //Add some people
    std::sort(list.begin(), list.end()); //Sort of the list
    for(int month = 1; month <= 12; month++)
        pref_months[month] += pref_months[month - 1]; //Count prefix sums for 1..12
    time_t t;
    struct tm *tm;
    int day, month;
    t = time(nullptr); //
    tm = localtime(&t); //Get localtime
    day = tm->tm_mday; //Get day
    month = tm->tm_mon; // Get month
    int today_duty = (pref_months[month - 1] + day) % list.size(); //Who is on duty
    std::cout << list[today_duty]; //Print, who is on duty
}