Question

The Fibonacci sequence is the sequence of numbers:

0, 1, 1, 2, 3, 5, 8, 13, 21, 34, …

The next number is found by adding up the two numbers before it.

For example, the 2 is found by adding the two numbers before it (1+1). The 3 is found by adding the two numbers before it (1+2). The 5 is found by adding the two numbers before it (2+3), and so on! Each number in the sequence is called a term.

In this exercise, you will need to:

1. Create the array int[] sequence that holds the values of the first 15 terms of the Fibonacci sequence. Think carefully about what happens to the index when iterating through the loop to fill this array. Read the Fibonacci description above to help!
2. Then print out the sequence of numbers seperated by a space.
3. Finally, create a method findIndex to find the index of the term 55.

Sample output:

Fibonacci sequence up to 15 terms:
0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 
Index position of 55 is: 10

Hint: You will need to use several loops: One to fill the array, one to print the array, and one to traverse the array!

Below is the coding given to change. Please use a template:

public class Fibonacci
{
public static void main(String[] args)
{

//number of elements to generate in the sequence
int max = 15;

// create the array to hold the sequence of Fibonacci numbers

//create the first 2 Fibonacci sequence elements
sequence[0] = 0;
sequence[1] = 1;

//create the Fibonacci sequence and store it in int[] sequence


//print the Fibonacci sequence numbers


System.out.println("\nIndex position of 55 is: " + findIndex(sequence, 55));

}

// This method finds the index of an element in an array

public static int findIndex (int[] arr, int n)
{

// your code goes here
}
}

Answer 1

public class Fibonacci {
    public static void main(String[] args) {

//number of elements to generate in the sequence
        int max = 15;

// create the array to hold the sequence of Fibonacci numbers
        int[] sequence = new int[max];

//create the first 2 Fibonacci sequence elements
        sequence[0] = 0;
        sequence[1] = 1;

//create the Fibonacci sequence and store it in int[] sequence
        for (int i = 2; i < sequence.length; i++) {
            sequence[i] = sequence[i - 1] + sequence[i - 2];
        }

        System.out.println("Fibonacci sequence up to 15 terms:");
        for (int i = 0; i < sequence.length; i++) {
            System.out.print(sequence[i] + " ");
        }
        System.out.println();

//print the Fibonacci sequence numbers
        System.out.println("\nIndex position of 55 is: " + findIndex(sequence, 55));
    }

    // This method finds the index of an element in an array
    public static int findIndex(int[] arr, int n) {
        for (int i = 0; i < arr.length; i++) {
            if (arr[i] == n)
                return i;
        }
        return -1;
    }
}