Sunday, February 2, 2020

Recursion(Fibonacci series)

Recursion(Fibonacci series)

In this tutorial another example of Recursion. You can see the detailed view of recursion in this post, where we discussed calculating the factorial of a number with recursion. Fibonacci series is a sequence of Fibonacci numbers like,

1,1,2,3,5,8,13,21,34,55,89,144,...

We can define this series in mathematical terms by the following expression,

We can summarise a recursive method to calculate the Fibonacci number for given value n as,

Calculating Fibonacci number is very easy, we can see in the following figure,


Example

public class DemoRecursion {// Calculate Fibonacci by recursion

    public static void main(String[] args) {
    DemoRecursion d=new DemoRecursion();
    //to print series
    for(int i=0;i<11;i++)
    {
        System.out.print(d.fibonacci(i)+"\t");
    }
    //System.out.println(d.fibonacci(9));
    }
    int fibonacci(int num)// Fibonacci recursive method
    {
        if(num==0)
        {
            return 0;
        }
        else if(num==1)
        {
            return 1;
        }
        else
        {
        return fibonacci(num-2)+fibonacci(num-1);
        }
    }
}
//***********************************************/

Output:
0 1 1 2 3 5 8 13 21 34 55

Video Tutorial