sona11

sona11

Fibonacci series using java

I wrote this code to calculate Fibonacci numbers by specifying the size. The results are correct, however the one thing that concerns me is the negative sign for some numbers in the larger range of size input.
here is the code

import java.util.Scanner;

public class FibonacciSeries {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int a, c = 0;
        int result = 0;
        int b = 1;

        Scanner scan = new Scanner(System.in);
        System.out.println("Enter the Number to display Fibonacci Series");
        a = scan.nextInt();

        System.out.println("Fibonacci Seriers is as follows");


        for (int i = 1; i <= a; i++) {
            System.out.print(" "+result+" ");
            result = c + b;
            b = c;
            c = result;

        }

    }

}

As previously said, this function calculates fibonacci numbers by selecting the size. I read the article about it here according to that findings are right however the one thing that bothers me is the negative sign for some values in the greater range of size input.

1- I couldn’t identify a mistake in the code; how can I remove the negative values from the output?
2- Why are there positive values following certain negative values? 3- The first negative value is -1323752223, followed by a positive number.

Thank you very much.

Most Liked

mindriot

mindriot

The problem you are having is integer overflow. The int allocates enough memory to hold a number within a range (specifically 32 bits giving a range of 2^-31 through 2^31 which is -2147483648 to 2147483647), when you add two numbers together and the result is larger then this than it overflows the memory available. Due to the way in which numbers are represented and added in binary, the effect it has is that it wraps around so 2147483647 + 1 = -2147483648.

You can look into integer overflows, to fully understand what is happening it is best to look at how numbers are represented in binary, twos complement, and how to do addition/subtraction. However for the problem at hand you have two options.

First you can use a long which allocates twice as much memory for the numbers and will give you a much larger range before you run into the same problem, but you will run into the same problem with big enough numbers. This is the easiest option, you should be able to just change “int” to “long” when declaring the variables and you will be good.

Alternatively you can look at something like the BigInteger class which will be able to allocate the right amount of memory to hold larger numbers as required, with some small costs in performance and being more awkward to use in some situations.

Where Next?

Popular Backend topics Top

dimitarvp
Hey everyone, I resumed work on my Elixir &lt;=&gt; SQLite library (which uses a Rust NIF underneath) and I am in a need of small and we...
New
ohm
Does anybody have good learning resources with regards to going into Event Driven Design, Architecture or Sourcing? I got recommended Er...
New
JimmyCarterSon
I am following this tutorial . I have followed carefully correcting errors as I go. The app allows you to create a blog post and add comm...
New
MarkIden
Hi, Recommend pls your favorite learning resources in Go, with best books, podcasts etc.
/go
New
Fl4m3Ph03n1x
Background PS: the following situation describes an hypothetical scenario, where I own a company that sells things to customers. I have ...
New
sona11
If isReachable throws an IOException in Java, what is the right step to do and why? The application, I believe, should halt the process ...
New
Fl4m3Ph03n1x
Background I have to queries that return a colossal amount of data on their own. I cannot use Repo.all as doing so would materialize thes...
New
pillaiindu
Currently reading the book “Programming Phoenix LiveView”. At the end of the Chapter 1, I’m trying to solve the guess game. If the user ...
New
jaeyson
Hi! I have clarifications (please correct me, as I mostly mix/confuse this details) with the following: The term RAG here where it read...
New
AstonJ
If you’re getting errors like this: psql: error: connection to server on socket “/tmp/.s.PGSQL.5432” failed: No such file or directory ...
New

Other popular topics Top

PragmaticBookshelf
Instantly view the changes you make to an app with stateful hot reload, and define a declarative UI in the same language as the app logic...
New
New
PragmaticBookshelf
Andy and Dave wrote this influential, classic book to help their clients create better software and rediscover the joy of coding. Almost ...
New
Exadra37
I am thinking in building or buy a desktop computer for programing, both professionally and on my free time, and my choice of OS is Linux...
New
AstonJ
There’s a whole world of custom keycaps out there that I didn’t know existed! Check out all of our Keycaps threads here: https://forum....
New
AstonJ
This looks like a stunning keycap set :orange_heart: A LEGENDARY KEYBOARD LIVES ON When you bought an Apple Macintosh computer in the e...
New
AstonJ
Was just curious to see if any were around, found this one: I got 51/100: Not sure if it was meant to buy I am sure at times the b...
New
New
First poster: bot
zig/http.zig at 7cf2cbb33ef34c1d211135f56d30fe23b6cacd42 · ziglang/zig. General-purpose programming language and toolchain for maintaini...
New
PragmaticBookshelf
25 puzzles that will make you a better C programmer by challenging your knowledge of the language, and explaining the technical details o...
New