How to get the Fibonacci of numbers like 8181?

Question

the result of the code below is : 3877337276612781506 but i tried online Fibonacci calculator and got huge number of more than 1000 decimals

in such numbers how can i got the Fibonacci result?

Long fnOfZero = 0L, fnOfOne = 1L, n, i, count = 8182L;
for (i = 2L; i < count; ++i){
  n = fnOfZero + fnOfOne;
  System.out.print(i + ":  ");
  System.out.println(n));
  fnOfZero = fnOfOne;
  fnOfOne = n;
}

What do you mean "the Fibonacci of numbers like 8181"? Fibonacci numbers are a sequence, not a function. — khelwood, Apr 18 '18 at 08:36
You didn't go look at how many bytes can be stored in a long. It sits at 8 bytes with a range of -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807. Your number cannot go higher because it's limited by the datatype — L_Church, Apr 18 '18 at 08:41
this is the function of fibonacci: `f{n}=f_{{n-1}} + f_{{n-2}}` — Paplusc, Apr 18 '18 at 08:42
If you use a biginteger instead of a long you will be able to store 100 digits whereas a long can only store 19 — L_Church, Apr 18 '18 at 08:44
If you want a `double` estimation: `Math.pow((1 + Math.sqrt(5))/2, n) / Math.sqrt(5)`; if value is too big for `double` you can work with *logarithms*. — Dmitry Bychenko, Apr 18 '18 at 08:47
Possible duplicate of [Large Numbers in Java](https://stackoverflow.com/questions/849813/large-numbers-in-java) — Ole V.V., Apr 18 '18 at 09:11

score 1 · Accepted Answer · answered Apr 18 '18 at 09:29

    BigInteger secondLast = BigInteger.ZERO;
    BigInteger last = BigInteger.ONE;
    int count = 8182;
    for (int i = 2; i < count; ++i) {
        BigInteger n = secondLast.add(last);
        secondLast = last;
        last = n;
    }
    System.out.println(last);

It prints a number with 1710 digits in it.

I used your algorithm and just substituted BigInteger for Long as already said in the comment.

score -1 · Answer 2 · answered Apr 18 '18 at 09:15

-1

You may give Big Decimal a try.

answered Apr 18 '18 at 09:15

Raj Roy

1
1

How to get the Fibonacci of numbers like 8181?

2 Answers2