01. Day of Week

#include <iostream>

using namespace std;

int main() {
    int number;
    cin >> number;

    switch (number) {
    case 1:
        cout << "Monday" << endl;
        break;
    case 2:
        cout << "Tuesday" << endl;
        break;
    case 3:
        cout << "Wednesday" << endl;
        break;
    case 4:
        cout << "Thursday" << endl;
        break;
    case 5:
        cout << "Friday" << endl;
        break;
    case 6:
        cout << "Saturday" << endl;
        break;
    case 7:
        cout << "Sunday" << endl;
        break;
    default:
        cout << "Error" << endl;
        break;
    }

    return 0;
}

Решение с тернарен оператор:

#include <iostream>

using namespace std;

int main() {
    int number;
    cin >> number;

    string dayOfWeek =
        number == 1 ? "Monday" :
        number == 2 ? "Tuesday" :
        number == 3 ? "Wednesday" :
        number == 4 ? "Thursday" :
        number == 5 ? "Friday" :
        number == 6 ? "Saturday" :
        number == 7 ? "Sunday" : "Error";

    cout << dayOfWeek << endl;

    return 0;
}