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Java Program to Display Fibonacci Series up to N

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Fibonacci sequence

Java program to display fibonacci sequence up to n has been shown here. Here n is the limit up to which the sequence is to be generated. For example if n = $20$, we get the fibonacci numbers up to $20$ i.e. $0, 1, 1, 2, 3, 5, 8, 13$. The following section covers the iterative and recursive approaches to find fibonacci sequence. The algorithm, pseudocode of the program have been shown below.






1. Algorithm to display fibonacci sequence upto n


1. Take the limit n as input.

2. Assign the first two fibonacci numbers to variables a, b i.e. a = 0 and b = 1

3. If n = 0, display a else, display a, b.

4. Check if a + b <= n

5. If step 4 is true perform step 6 to 8, else stop the process

6. t = a + b and display t

7. a = b and b = t

8. Go to step 4




2. Pseudocode to display fibonacci sequence upto n


Input : A limit $n$

Output : Fibonacci sequence upto $n$

1. Procedure fibonacciUptoN($n$):

2. $a \leftarrow 0$

3. $b \leftarrow 1$

4. If $n == 0$:

5. Display $a$

6. Else:

7.Display $a, b$

8. Repeat until $a + b \leq n$:

9. $t \leftarrow a + b$

10.Display $t$

11.$a \leftarrow b$

12.$b \leftarrow t$

13. End Procedure





3. Java Program & output to display fibonacci sequence upto n using iteration

Code has been copied
/*******************************
	  alphabetacoder.com
Java program to find fibonacci 
series up to N using iteration
********************************/

import java.util.Scanner;

class Main {
    public static void main(String args[]) {
        // declare object of Scanner class
        Scanner sc = new Scanner(System.in);

        // declare variables
        int n, a, b, t = 0;

        // take input of the limit
        System.out.print("Enter the limit = ");
        n = sc.nextInt();

        // intialize the first two terms of the sequence
        a = 0;
        b = 1;

        System.out.print("Fibonacci sequence upto " + n + ": ");
        // display the first fibonacci
        if (n == 0)
            System.out.print(a);
        // display first two fibonacci
        else
            System.out.print(a + " " + b);

        //now calculate the remaining terms upto n
        while (a + b <= n) {
            // calculate next fibonacci
            t = a + b;
            //display next fibonacci
            System.out.print(t + " ");

            //assign values for next iteration
            a = b;
            b = t;
        }
    }
}

Output

Enter the limit = 20

Fibonacci sequence upto 50: 0 1 1 2 3 5 8 13





4. Java Program & output to display fibonacci sequence upto n using recursion

Code has been copied
/*******************************
	alphabetacoder.com
Java program to find fibonacci 
series up to N using iteration
********************************/

import java.util.Scanner;

class Main {
    // recursive function to display
    // fibonacci sequence
    static void fibonacci(int a, int b, int n) {
        if (a <= n) {
            System.out.print(a + " ");
            fibonacci(b, a + b, n);
        }
    }

    public static void main(String args[]) {
        // declare object of Scanner class
        Scanner sc = new Scanner(System.in);

        // declare variables
        int n;

        // take input of the limit
        System.out.print("Enter the limit = ");
        n = sc.nextInt();

        System.out.print("Fibonacci sequence upto " + n + ": ");
        // call the function
        // pass value of the first two 
        // terms and limit
        fibonacci(0, 1, n);
    }
}

Output

Enter the limit = 50

Fibonacci sequence upto 50: 0 1 1 2 3 5 8 13 21 34





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