using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication12
{
    class Program
    {
        static void Main(string[] args)
        {
            for (int cicles = 0; cicles >= 0; cicles++)
            {
                Console.WriteLine("Press 1 for Fibonacci \nPress 2 for multiplication table\nPress 3 for 5 digits number revesor \nPress 4 for prime number checker");
                int actionNum = int.Parse(Console.ReadLine());
                if (actionNum == 1)
                {
                    Console.Write("Insert amount of numbers you'd like the program to calculate: ");
                    int fiboNum = int.Parse(Console.ReadLine());
                    Console.WriteLine("0\n1");
                    double a1 = 0;
                    double a2 = 1;
                    for (int i = 0; i < (fiboNum - 2); i++)
                    {
                        double a3 = a1 + a2;
                        Console.WriteLine(a3);
                        a1 = a2;
                        a2 = a3;
                    }
                    Console.WriteLine();
                }
                if (actionNum == 2)
                {
                    for (int a = 1; a <= 10; a++)
                    {
                        for (int b = 1; b <= 10; b++)
                            Console.Write(a * b +" ");
                        Console.WriteLine();
                    }
                    Console.WriteLine();
                }
                if (actionNum == 3)
                {
                    Console.Write("Please insert a 5-digits number: ");
                    int numTBR = int.Parse(Console.ReadLine());
                    int dig1 = numTBR % 10;
                    int dig2 = (numTBR / 10) % 10;
                    int dig3 = (numTBR / 100) % 10;
                    int dig4 = (numTBR / 1000) % 10;
                    int dig5 = (numTBR / 10000) % 10;
                        Console.WriteLine("Reversed number is " + dig1 + "" + dig2 + "" + dig3 + "" + dig4 + "" + dig5 +"\n");
                }
                if (actionNum == 4) //prime number checker
                {
                    Console.Write("Insert number (an integer that is greater than 1): ");
                    int primeInQuestion = int.Parse(Console.ReadLine());
                    int div = 0;
                    int antiMultiMessage = 0;
                    for (int i = primeInQuestion; i > 1; i--)
                    {
                        if (i != primeInQuestion && primeInQuestion % i == 0 && primeInQuestion!=2 && antiMultiMessage == 0)
                        {
                            Console.WriteLine(primeInQuestion + " is not a prime.");
                            div = i;
                            antiMultiMessage = 1;
                            //Console.WriteLine(i);
                        }
                        if (div==0 && i<3 && primeInQuestion%3!=0 && primeInQuestion%2!=0)
                            Console.WriteLine(primeInQuestion + " is a prime number.");
                    }
                    if (primeInQuestion == 2 || primeInQuestion== 3)
                        Console.WriteLine(primeInQuestion + " is a prime number.");
                    Console.WriteLine();
                }
            }
        }
    }
}