//CATUNGAL, MARK ANGELO S.

//CCP 1103 - ITBC

//FIBONACCI FREEZE

​

using System;

​

namespace SumofSequence

{

    public class Program

    {

        public static void Main(string[] args)

        {

            int number;

            int firstNumber;

            int secondNumber;

            int sequence;

            string input;

​

            Console.WriteLine("Fibonacci Freeze");

            Console.Write("Enter a number: ");

            input = Console.ReadLine();

            if (Int32.TryParse(input, out number) == true)

            {

                firstNumber = 0;

                secondNumber = 1;

                sequence = 0;

                if(number > 0)

                {

                    if (number <= 50)

                    {

                        for (int i = 1; i <= number; i++)

                        {

                            sequence = firstNumber + secondNumber;

                            firstNumber = secondNumber;

                            secondNumber = sequence;

                        }

                        Console.WriteLine("The fibonacci number for {0} is {1}.", number,firstNumber);

                    }

                    else

                    {

                        Console.WriteLine("Invalid input. Please enter 1-50 input only.");

                    }

                }

                else

                {

                    Console.WriteLine("Zero or negative input is not allowed.");

                }

            }

            else

            {

                Console.WriteLine("Invalid input.Please enter a numeric value.");

            }

        }

    }

}