P2C2: Write a program in C Sharp for fibonacci numbers using iteration and recursion method.

Fibonacci Series:

Fibonacci series is the sequence of the numbers which has following properties:

1. First number is 1.
2. Second number is 1
3. Remaining other numbers are sum of their preceding numbers. Eg: third number = 1+1=2
4. Fibonacci series: 1, 1, 2, 3, 5, 8, 13, ....

------------------------------------------------------------------

//Source code using iteration method

using System;

public class Program_Fibonacci_Iteration

{

   public static void Main()

    {

        int num;

        long ans;

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

        num = Convert.ToInt32(Console.ReadLine());

        ans = Fibo(num);

        Console.WriteLine("\n :::::::: OUTPUT :::::::::\n");

        Console.WriteLine("The " + num + " th number in fibonacci series is: \n" + ans);

       

        Console.WriteLine("\n\nPress any key to exit...");

        Console.ReadLine();

    }

   static int Fibo(int n)

   {

       int num1 = 1, num2 = 1;

       int num3 = 0;

       if (n <= 2)

           return 1;

       else

       {

           for (int i = 3; i <= n; i++)

           {

               num3 = num1 + num2;

               num1 = num2;

               num2 = num3;

           }

           return num3;

       }

   }

}

OUTPUT

Enter any number: 8

 :::::::: OUTPUT :::::::::

The 8 th number in fibonacci series is:

21

Press any key to exit...

-------------------------------------------------------------------

//Source code using recursion method
using System;

public class Program_Fibonacci_Recursion
{
   public static void Main()
    {
        int num;
        long ans;

        Console.Write("Enter any number: ");
        num = Convert.ToInt32(Console.ReadLine());

        ans = Fibo(num);
        Console.WriteLine("\n :::::::: OUTPUT :::::::::\n");
        Console.WriteLine("The " + num + " th number in fibonacci series is: \n" + ans);
     
        Console.WriteLine("\n\nPress any key to exit...");
        Console.ReadLine();
    }

   static int Fibo(int n)
   {
       if (n <= 2)
           return 1;
       else
           return (Fibo(n-1) + Fibo(n-2));
   }

}

OUTPUT

Enter any number: 8

 :::::::: OUTPUT :::::::::

The 8 th number in fibonacci series is:

21

Press any key to exit...

---------------------------------------------------------------
//Printing Fibonacci Series
using System;

public class Program_Fibonacci_Recursion
{
   public static void Main()
    {
        int n, num1, num2, num3;
        num1 = 1; //First fibonacci number
        num2 = 1; //Second fibonacci number
     
        Console.Write("Enter any number: ");
        n = Convert.ToInt32(Console.ReadLine());

        Console.WriteLine("\n\n:::::::: OUTPUT :::::::::");
     
        //To print first and second fibonacci numbers
        Console.WriteLine("Position: " + 1 + "\tValue: " + num1);
        Console.WriteLine("Position: " + 2 + "\tValue: " + num2);

       //Counting for fibonacci number starts from third, so i = 3 is assigned
        for (int i = 3; i <= n; i++)
        {
            num3 = num1 + num2;
            num1 = num2;
            num2 = num3;
            Console.WriteLine("Position: " + i + "\tValue: " + num3);
        }
           
        Console.WriteLine("\n\nPress any key to exit...");
        Console.ReadLine();
    }
}

OUTPUT

Enter any number: 12

:::::::: OUTPUT :::::::::

Position: 1     Value: 1

Position: 2     Value: 1

Position: 3     Value: 2

Position: 4     Value: 3

Position: 5     Value: 5

Position: 6     Value: 8

Position: 7     Value: 13

Position: 8     Value: 21

Position: 9     Value: 34

Position: 10    Value: 55

Position: 11    Value: 89

Position: 12    Value: 144

Press any key to exit...