## Fibonacci series in Java using recursion

### Fibonacci series in practical:

Fibonacci series using recursion 1 :

import java.util.Scanner;

public class Main

{

public static int Fibonacci(int n)

{

if (n <= 1)

return n;

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

}

public static void main(String args[])

{

Scanner sc = new Scanner(System.in);

int n, sum = 0;

System.out.println(“Enter the nth value: “);

n = sc.nextInt();

System.out.println(“Fibonacci series: “);

while(Fibonacci(sum) <= n)

{

System.out.print(Fibonacci(sum) + ” “);

sum++;

}

}

}

Fibonacci series using recursion 2 :

class FibonacciExample2{

static int n1=0,n2=1,n3=0;

static void printFibonacci(int count){

if(count>0){

n3 = n1 + n2;

n1 = n2;

n2 = n3;

System.out.print(” “+n3);

printFibonacci(count-1);

}

}

public static void main(String args[]){

int count=10;

System.out.print(n1+” “+n2);//printing 0 and 1

printFibonacci(count-2);//n-2 because 2 numbers are already printed

}

}

### Fibonacci series in Theory :

we’ll talk about to write a code to find a

Fibonacci series so we’ll bring this

have to let let’s start with one so and

then one basically we have before one

will be having a 0 so 0 plus 1 is 1 then

this 1 plus 1 is 2 then 1 plus 2 is 3 2

plus 3 is 5 3 + 5 is 8 and 5 plus 8 is

13 and so so on so when to plane this

series still our number n ok so anyway n

may be any valuable it’s a 50 or 70 or 2

hundreds maybe it may be any number so

in order to implement Fibonacci series

what we’ll do is we’ll use a main

function here which is obviously void

main now so for this we need some

variables so first we’ll say a variable

is K then a variable a and B just to

make it simple so we have these three

variables by default the value of K will

be 0 ok we’ll run a while loop till what

point I want to go with this series so

we’ll say till the point let’s say 50 so

maximum value I want is 50 ok or equal

to 50 m so I don’t know if 50 lies

between this series but let’s say if

this values is less than is equal to 50

then we have to print now what we to do

is we will say the initial value for

this this a is 1 and B is also 1 okay

and let’s print the value of a and B so

how to print the value of a and B will

say us out and we’ll print without

giving us new line will print the value

1 and 1 because this is what we want

right 1 1 and then I will find K so k is

equal to a plus B now when you say a

plus B so a value is 1 and B value is 1

which simply means this is 1 and 1 the K

value will be 2 and now let us print

that too so how to print 2 will say

let’s print the value of K with

space okay now if you plan this if I

high speed space here also knife Adam

this it will print one one and the next

K value which is K simple now next in

the next iteration what I do is I will

just change the value of a as one and

and the be ash tube so what I mean by

that is I can simply say a equal to B so

the value of a becomes P so we have to

shift those parameters and

the value of B will be key

okay and now if you shape this it will

bring the whole series so that’s it we

are just printing values and then we are

saying yeah we’re painting values right

so if I run this now so you can this is

your Fibonacci series so it is 1 1 and

all this values okay so since we are

checking we are checking first and then

adding the value so that’s why it is

fitting in this way okay so it is going

beyond 50 so you can also do here let’s

say if you can check with if condition

and again you can print it but that’s

the way we do it right so yeah so this

is how we are to print we can also take

this input which is value of 50 from

user so we can use a scanner plus here

to take the input so in that scenario we

have to use a scanner class will say

scanner is equal to new scanner okay I

am this we have to mention from where I

will be getting the input so with the

system input device I let’s import the

package so in that means you can just

simply type ctrl shift I which will

import the package and then we can

simply take will take a variable which

is n equal to SC dot next int which is

here okay and then we’ll ask user to

enter value so we’ll say enter any

number now instead of writing 50 here we

can type n okay if I save and if you run

this so it’s waiting for a number I will

say a 22 so that’s the answer so it’s

just go beyond 34 22 right so you can

also change it so

what you can do is you can simply say

before printing if a case less than

equal to n will say break but we have

multiple ways to solve this so this is

one of the way to solve that problem so

if I said you need to now just made a

mistake it should be greater so if I run

this and if I say 22 now so it will

print all the values till 21 okay if I

gave a different value so let’s say if I

gave one thousand and a big number

10,000 so it will print all the

Fibonacci series number you that’s the

last number because if you add this

number and this it will go beyond ten

thousand clear so this is how we have to

find the Fibonacci series