Fibonacci sequence without using Array [closed]

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I am trying to practice JAVA by coding a Fibonacci sequence in which the user can declare the length of the Fibonacci starting from 0 to n. Here is my code:

public class test {
public static void main(String args[]) throws IOException {
    BufferedReader pao = new BufferedReader(
            new InputStreamReader(System.in));

    System.out.print("Enter number: ");
    String enter = pao.readLine();
    int ent = Integer.parseInt(enter);

    int total1 = 0;
    int total2 = 1;
    int total3 = 0;

    for (int a = 0; a < ent; a++) {
        if (a <= 1) {
            System.out.print(" " + total3);
            total3 = total1 + total2;

        } else if (a == 2) {
            System.out.print(" " + total3);
        } else {
            total1 = total2;
            total2 = total3;
            total3 = total1 + total2;
            System.out.print(" " + total3);

        }
    }

}
}

Is there another way to do this in a much more simpler, shorter and "Nicer" way? still without using arrays. Thank you in advance.

@user2336315 thank you for that info. I wasn't aware that there's a place for code reviews. — Juan Paolo Tarroja
– Juan Paolo Tarroja, Commented Nov 7, 2014 at 18:53
@RC. Thank you. I'm new to JAVA so I'm still not familiar to some methods — Juan Paolo Tarroja
– Juan Paolo Tarroja, Commented Nov 7, 2014 at 18:55
@Scar: just be sure to check the What topics can I ask about here? page for Code Review first. (For that matter, since you're new here, you should read the corresponding page for Stack Overflow as well). — Daniel Pryden
– Daniel Pryden, Commented Nov 7, 2014 at 19:22

Karo · Accepted Answer · 2014-11-07 18:32:01Z

3

You can use recursive fibonacci but it will increase your runtime from O(n) to O(2^n) it's like bellow

int fib(int n) {
   if (n <= 1)
      return n;
   return fib(n-1) + fib(n-2);
}

and there is another way that decrease your runtime to O(log n) but it use arrays (Using power of the matrix {{1,1},{1,0}}) you can read about it here. also for above recursion if you use array you can change runtime to O(n) again by method call dynamic programming.

answered Nov 7, 2014 at 18:32

Karo

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pushkin · Accepted Answer · 2018-06-17 14:07:53Z

1

public class Fibo {
    public static void main(String[] args) {
        int n = 12;
        int a = 0;
        int b = 1;

        System.out.print(a + " ");
        System.out.print(b + " ");
        for (int i = 0; i < n-2; i++) {
            int temp = a + b;
            a = b;
            b = temp;
            System.out.print(temp+" ");         
        }
    }
}

edited Jun 17, 2018 at 14:07

pushkin

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answered Jun 17, 2018 at 14:05

Arunava Bagal

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Comments

Vikas Verma · Accepted Answer · 2014-11-07 18:25:45Z

0

Using recursion :

public int fibonacci(int n)  {
    if(n == 0)
        return 0;
    else if(n == 1)
      return 1;
   else
      return fibonacci(n - 1) + fibonacci(n - 2);
}

answered Nov 7, 2014 at 18:25

Vikas Verma

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Comments

Community · Accepted Answer · 2017-05-23 12:24:03Z

0

Your iterative solution is fine (although there are other nitpicks I would make if this were a code review). The recursive implementation would win you more style points, but it is substantially slower and more memory-intensive.

For maximum style points(*), you can also use Binet's formula for a closed-form solution for the Fibonacci sequence.

(*) Don't do this in production code, though, unless you're really, really sure you need it.

edited May 23, 2017 at 12:24

CommunityBot

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answered Nov 7, 2014 at 18:34

Daniel Pryden

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Comments

pheng · Accepted Answer · 2024-05-13 17:53:03Z

0

int x = 10, i=0, f=1, s=1, o = 1;
while (x > 0) {
    if(i!=0 && i!=1){
        o=f+s;
        f=s;
        s=o;
    }
    System.out.print(o);
    x--;
    i++;
}

answered May 13, 2024 at 17:53

pheng

1

1 Comment

General Grievance Over a year ago

1) Wrong print function. 2) A for loop with only i changing from 0 to 10 will do just fine here. x seems unnecessary.

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