Fibonacci series is a series of numbers where the next
number is the sum of the previous two numbers behind it. It has the starting
two numbers predefined as 0 & 1. The series goes on like this:

0,1,1,2,3,5,8,13,21,34,55,89,144,233,377……..

Here we illustrate two techniques for the creation of the Fibonacci Series to n terms. The For Loop method & the Recursive Technique. Check them below.

The For Loop technique requires that we create some variables and keep track of the latest two terms('First' & 'Second'). Then we calculate the next term by adding these two terms & setting a new set of two new terms. These terms are the 'Second' & 'Newest'.

using System; using System.Text; using System.Threading.Tasks;

namespace Fibonacci_series_Using_For_Loop

{

class Program

{

static void Main(string[] args)

{

int n, first = 0, second = 1, next, c;

Console.WriteLine("Enter the number of terms");

n = Convert.ToInt16(Console.ReadLine());

Console.WriteLine("First "+ n +" terms of Fibonacci series are:");

for (c = 0; c < n; c++)

{

if (c <= 1)

next = c;

else

{

next = first + second;

first = second;

second = next;

}

Console.WriteLine(next);

}

Console.ReadKey();

}

}

}

The recursive technique to a Fibonacci series requires the
creation of a function that returns an integer sum of two new numbers. The
numbers are one & two less than the number supplied. In this way final
output value has each number added twice excluding 0 & 1. Check the program
below.

using System; Using System.Text; using System.Threading.Tasks;

namespace Fibonacci_Series_Recursion

{

class Program

{

static void Main(string[] args)

{

int n, i = 0, c;

Console.WriteLine("Enter the number of terms");

n=Convert.ToInt16(Console.ReadLine());

Console.WriteLine("First 5 terms of Fibonacci series are");

for ( c = 1 ; c <= n ; c++ )

{

Console.WriteLine(Fibonacci(i));

i++;

}

Console.ReadKey();

}

static int Fibonacci(int n)

{

if (n == 0)

return 0;

else if (n == 1)

return 1;

else

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

}

}

}