Different ways of writing the Fibonacci Series in Java Program

Category : Java | Sub Category : Java Programs | By Prasad Bonam Last updated: 2020-10-02 14:26:54 Viewed : 398

Different ways of writing  the Fibonacci Series in Java Program

Fibonacci Series: is the collection of numbers in a sequence known as the Fibonacci Series where each number after the first two numbers is the sum of the previous two numbers. The series generally goes like 1, 1, 2, 3, 5, 8, 13, 21 and so on.

  fib(n) = fib(n - 1) + fib(n - 2)

1. Fibonacci Series – Using For Loop

FibonacciForLoop.java

package runnerdev;

import java.util.Scanner;

public class FibonacciForLoop {

            public static void main(String[] args) {

                        Scanner sc = new Scanner(System.in);

                        System.out.println("Enter number of terms: ");

                        int n = sc.nextInt();

                        int i = 0, j = 1, nextTerm;

                        System.out.println("Fibonacci series is:  ");

                        for (int f = 0; f < n; f++) {

                                    if (f <= 1)

                                                nextTerm = f;

                                    else {

                                                nextTerm = i + j;

                                                i = j;

                                                j = nextTerm;

                                    }

                                    System.out.println(nextTerm);

                        }

            }

}

 Out Put:

2.   Fibonacci Series – Using While Loop 

FibonacciWhileLoop.java

package runnerdev;

 

import java.util.Scanner;

 

public  class FibonacciWhileLoop {

            public static void main(String[] args) {

                        Scanner sc = new Scanner(System.in);

                        System.out.println("Enter number of terms: ");

                        int n = sc.nextInt();

                        int first = 0, second = 1, next;

                        System.out.println("Fibonacci series is: ");

                        int i = 0;

                        while (i < n) {

                                    if (i <= 1)

                                                next = i;

                                    else {

                                                next = first + second;

                                                first = second;

                                                second = next;

                                    }

                                    System.out.println(next);

                                    i++;

                        }

            }

}

OutPut:

3.   Fibonacci Series –  using Static Method

FibonacciWithStatic.java

import java.util.Scanner;

 

public class FibonacciWithStatic {

            public static void main(String[] args) {

                        Scanner sc = new Scanner(System.in);

                        System.out.println("Enter number of terms: ");

                        int n = sc.nextInt();

                        series(n);

            }

 

            static void series(int num) {

                        System.out.println("Fibonacci series is:  ");

                        int i = 0, j = 1, next;

                        for (int c = 0; c < num; c++) {

                                    if (c <= 1)

                                                next = c;

                                    else {

                                                next = i + j;

                                                i = j;

                                                j = next;

                                    }

                                    System.out.print(next + " ");

                        }

            }

}

OutPut:

4. Fibonacci Series –  Using Recursion

package runnerdev;

 

import java.util.Scanner;

 

public class FibonacciRecursion {

            int f = 0, i = 0, j = 1, next;

 

            void fib(int n) {

                        if (n > 0) {

                                    if (f <= 1)

                                                next = f;

                                    else {

                                                next = i + j;

                                                i = j;

                                                j = next;

                                    }

                                    System.out.print(next + " ");

                                    f++;

                                    fib(--n);

                        }

            }

 

            public static void main(String[] args) {

                        Scanner sc = new Scanner(System.in);

                        System.out.println("Enter number of terms: ");

                        int num = sc.nextInt();

                        FibonacciRecursion f = new FibonacciRecursion();

                        System.out.println("Fibonacci series is:  ");

                        f.fib(num);

            }

}

Output:

5. Fibonacci Series –  Simple way

FibonacciIfCondition.java

import java.util.Scanner;

 

 

public class FibonacciIfCondition {

 

            public static int fib(int n) {

                        if (n <= 1)

                                    return n;

                        else

                                    return fib(n - 1) + fib(n - 2);

            }

 

            public static void main(String[] args) {

 

                        Scanner sc = new Scanner(System.in);

                        System.out.println("Enter number of terms: ");

                        int num = sc.nextInt();

                        System.out.println("Fibonacci series is: ");

                        for (int i = 0; i < num; i++) {

                                    System.out.println(fib(i));

                        }

 

            }

 

}

Output:

6. Fibonacci Series –  using Java8

<int[]> Stream<int[]> java.util.stream.Stream.iterate(int[] seed, UnaryOperator<int[]> f)

 

Returns an infinite sequential ordered Stream produced by iterative application of a function f to an initial element seed, producing a Stream consisting of seed, f(seed), f(f(seed)), etc.

The first element (position 0) in the Stream will be the provided seed. For n > 0, the element at position n, will be the result of applying the function f to the element at position n - 1.

Type Parameters:

<T> the type of stream elements

Parameters:

seed the initial element

f a function to be applied to to the previous element to produce a new element

Returns:

a new sequential Stream

Syntax:

    public static<T> Stream<T> iterate(final T seed, final UnaryOperator<T> f) {

        Objects.requireNonNull(f);

        final Iterator<T> iterator = new Iterator<T>() {

            @SuppressWarnings("unchecked")

            T t = (T) Streams.NONE;

 

            @Override

            public boolean hasNext() {

                return true;

            }

 

            @Override

            public T next() {

                return t = (t == Streams.NONE) ? seed : f.apply(t);

            }

        };

        return StreamSupport.stream(Spliterators.spliteratorUnknownSize(

                iterator,

                Spliterator.ORDERED | Spliterator.IMMUTABLE), false);

    }

 

<Integer> Collector<Integer, ?, List<Integer>> java.util.stream.Collectors.toList()

Returns a Collector that accumulates the input elements into a new List. There are no guarantees on the type, mutability, serializability, or thread-safety of the List returned; if more control over the returned List is required, use toCollection(Supplier).

Type Parameters:

<T> the type of the input elements

Returns:

a Collector which collects all the input elements into a List, in encounter order

Syntax:

    public static <T>

    Collector<T, ?, List<T>> toList() {

        return new CollectorImpl<>((Supplier<List<T>>) ArrayList::new, List::add,

                                   (left, right) -> { left.addAll(right); return left; },

                                   CH_ID);

    }

FibonacciwithJava8.java

package runnerdev;

import java.util.List;

import java.util.Scanner;

import java.util.stream.Stream;

import static java.util.stream.Collectors.toList;

public class FibonacciwithJava8 {

            public static List<Integer> getFibonacci(int series) {

                        return Stream.iterate(new int[] { 0, 1 }, f -> new int[] { f[1], f[0] + f[1] }).limit(series).map(n -> n[0])

                                                .collect(toList());

            }

            public static void main(String[] args) {

                        Scanner sc = new Scanner(System.in);

                        System.out.println("Enter number of terms: ");

                        int num = sc.nextInt();

                        List<Integer> fibonacci = getFibonacci(num);

                        System.out.println("Fibonacci series is: ");

                        fibonacci.forEach(x -> System.out.println(x));

            }

}

Output: