## Thursday, September 20, 2018

This post explains, how to write a program to print Fibonacci Series in java programming language. In Mathematics, Fibonacci series next number is the sum of previous two numbeprs for example 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55 etc. The first two numbers of Fibonacci series are 0 and 1.

If you observe the above pattern, First Value is 0, Second Value is 1 and the subsequent number is the result of sum of the previous two numbers. For example, Third value is (0 + 1), Fourth value is (1 + 1) so on and so forth.

In mathematical terms, the sequence Fn of Fibonacci numbers is defined by the recurrence relation
Fn = Fn-1 + Fn-2
with seed values
F0 = 0 and F1 = 1.

There are two ways to write the fibonacci series program in java:
• Fibonacci Series without using recursion
• Fibonacci Series using recursion

## Fibonacci Series in Java without using recursion

Let's see the Fibonacci series program in java without using recursion.
```class FibonacciExample1{
public static void main(String args[])
{
int n1=0,n2=1,n3,i,count=10;
System.out.print(n1+" "+n2);//printing 0 and 1

for(i=2;i<count;++i)//loop starts from 2 because 0 and 1 are already printed
{
n3=n1+n2;
System.out.print(" "+n3);
n1=n2;
n2=n3;
}
}
} ```

## Fibonacci Series using recursion in java

Let's see the Fibonacci series program in java using recursion.
```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
}
}  ```

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