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Java

Posted by johnsdoe
johnsdoe
Courses Plus Student 4,920 Points

Fibonacci Series in Java

I was looking for a code to write the Fibonacci Series in Java and I've found this one:

public class fibonacci {
    public static void main(String args[]) {
        int n1 = 0, n2 = 1, n3, i, display = 10;
        System.out.print(n1 + " " + n2); //printing 0 and 1

        for (i = 1; i <= display; i++) //loop starts
        {
            n3 = n1 + n2;
            System.out.print(" " + n3);
            n1 = n2;
            n2 = n3;
        }

    }
}

THE RESULT IS: 0 1 1 2 3 5 8 13 21 34 55 89 (Where every number is a summation of previous two number, except for the first two number shown in result)

MY QUESTION IS: What dose the n1 = n2; and n2 = n3; represent? Please explain.

1 Answer

Jason Anders
MOD
Jason Anders
Treehouse Moderator 145,863 Points
Jason Anders
Jason Anders
Treehouse Moderator 145,863 Points

Hi Shamir,

Those two lines are re-assigning values to the variables after the loop runs and before the loop runs again.

Before the loop begins, n1 is initialized to 0 -- n2 is initialized to 1 -- and n3 is just declared, but not initialized until inside the loop at n3 = n1 + n2.

So, the first iteration of the loop, n3 becomes 1 + 0 (which equals 1). Then the re-assignments happen. n1 now becomes 1, and n2 also becomes 1.
The loop runs again, and this time n3 becomes 1 + 1 (which equals 2). Then the re-assignments... n1 is now 1 and n2 is now 2.
And so on...

I hope this helped. :)

Keep coding! :dizzy:

johnsdoe
johnsdoe
Courses Plus Student 4,920 Points

Hi Jason, You explained it very well. Thank you so much!