C# Program to Print Nth Number in Fibonacci Series Recursive Approach

Write a C# Program to Print Nth Number in Fibonacci Series Recursive Approach?

What is Fibonacci Series?

Fibonacci series is a sequence of numbers in below order:

0, 1, 1, 2, 3, 5, 8, 13, 21, 34… The next number is found by adding up the two numbers before it.

The formula for calculating these numbers is:

F(n) = F(n-1) + F(n-2)

where:

F(n) is the term number.

F(n-1) is the previous term (n-1).

F(n-2) is the term before that (n-2).

it starts either with 0 or 1.

Different ways to print Fibonacci Series in C#?

In C#, there are several ways to print Fibonacci Series.

1. Iterative Approach
2. Recursion Approach

Recursive Approach:

In this approach, We need to pass the length of the Fibonacci Series to the recursive method and then it iterates continuously until it reaches the goal.

namespace ConsoleApplication

{

    class Program

    {

        public static int FibonacciSeries(int n)

        {

            if (n == 0) return 0; //To return the first Fibonacci number

            if (n == 1) return 1; //To return the second Fibonacci number

            return FibonacciSeries(n - 1) + FibonacciSeries(n - 2);

        }

        public static void Main(string[] args)

        {

            Console.Write("Enter the length of the Fibonacci Series: ");

            int length = Convert.ToInt32(Console.ReadLine());

            for (int i = 0; i < length; i++)

            {

                Console.Write("{0} ", FibonacciSeries(i));

            }

            Console.ReadKey();

        }

    }

}

Output:

here's a C# program to print the Nth number in the Fibonacci series using a recursive approach:

Enter the length of the Fibonacci Series: 12

0112358 13 21 34 55 89.

using System;

class Program

{

    // Recursive function to calculate the Nth Fibonacci number

    static int Fibonacci(int n)

    {

        if (n <= 1)

            return n;

        return Fibonacci(n - 1) + Fibonacci(n - 2);

    }

    static void Main(string[] args)

    {

        int n = 10; // Change this to get different Fibonacci numbers

        if (n <= 0)

        {

            Console.WriteLine("Invalid input. Please enter a positive integer.");

        }

        else

        {

            Console.WriteLine($"The {n}th number in the Fibonacci series is: {Fibonacci(n)}");

        }

    }

}

In this program:

• The Fibonacci function is a recursive function that calculates the Nth Fibonacci number.
• In the Main method, you can change the value of n to get the Nth Fibonacci number you desire.
• The program checks if the input n is a positive integer and prints the Nth Fibonacci number accordingly.