#include <cmath>
#include <iostream>

long long fib(long long n);
long long factorial(long long num);

int main(int argc, char* argv[])
{
    using namespace std;

    const long double Pi = 3.1415926535897932;
    float num;

    if (argc > 1)
        num = atoi(argv[1]);
    else {
        cout << "Enter a number: ";
        cin >> num;
        cout << endl;
    }

    cout << "square " << num * num << endl;
    cout << "cube " << num * num * num << endl;
    cout << "sqrt " << sqrt(num) << endl;
    if (num > -1 && num < 21) {
        if (num != 0) {
            cout << "fib " << fib(num) << endl;
        }
        cout << "factorial " << factorial(num) << endl;
    }
    if (num > -1) {
        cout << "area of a circle " << Pi * num * num << endl;
    }
    cout << "cos " << cos(num) << endl;
    cout << "acos " << acos(num) << endl;
    cout << "sin " << sin(num) << endl;
    cout << "asin " << asin(num) << endl;
    cout << "tan " << tan(num) << endl;
    cout << "atan " << atan(num) << endl;

    return 0;
}

long long fib(long long n)
{
    long long fib0 = 0, fib1 = 1, temp, count = 1;
    while (count != n) {
        temp = fib1;
        fib1 = fib0 + fib1;
        fib0 = temp;
        count++;
    }
    return fib1;
}

long long factorial(long long n)
{
    long long num = 1;
    for (int i = 1; i <= n; i++) {
        num *= i;
    }
    return num;
}