Abstract Fibonacci

import java.util.ArrayList;  
import java.util.HashMap;
import java.util.stream.Stream;

/* Objective will require changing to abstract class with one or more abstract methods below */
abstract class Fibo {
    String name;  // name or title of method
    int size;  // nth sequence
    int hashID;  // counter for hashIDs in hash map
    ArrayList<Long> list;   // captures current Fibonacci sequence
    HashMap<Integer, Object> hash;  // captures each sequence leading to final result

    /*
     Zero parameter constructor uses Telescoping technique to allow setting of the required value nth
     @param: none
     */
    public Fibo() {
        this(20); // telescope to avoid code duplication, using default as 20
    }

    /*
     Construct the nth fibonacci number
     @param: nth number, the value is constrained to 92 because of overflow in a long
     */
    public Fibo(int nth) {
        this.size = nth;
        this.list = new ArrayList<>();
        this.hashID = 0;
        this.hash = new HashMap<>();
        //initialize fibonacci and time mvc
        this.init();
    }

    /*
     This Method should be "abstract"
     Leave method as protected, as it is only authorized to extender of the class
     Make new class that extends and defines init()
     Inside references within this class would change from this to super
     Repeat process using for, while, recursion
     */
    protected abstract void init();

    /*
     Number is added to fibonacci sequence, current state of "list" is added to hash for hashID "num"
     */
    public void setData(long num) {
        list.add(num);
        hash.put(this.hashID++, list.clone());
    }

    /*
     Custom Getter to return last element in fibonacci sequence
     */
    public long getNth() {
        return list.get(this.size - 1);
    }

    /*
     Custom Getter to return last fibonacci sequence in HashMap
     */
    public Object getNthSeq(int i) {
        return hash.get(i);
    }

    /*
     Console/Terminal supported print method
     */
    public void print() {
        System.out.println("Init method = " + this.name);
        System.out.println("fibonacci Number " + this.size + " = " + this.getNth());
        System.out.println("fibonacci List = " + this.list);
        System.out.println("fibonacci Hashmap = " + this.hash);
        for (int i=0 ; i<this.size; i++ ) {
            System.out.println("fibonacci Sequence " + (i+1) + " = " + this.getNthSeq(i));
        }
    }
}

Fibonacci - For and While Loop (Extends)

In this display, we see how firstTerm = 0 and secondTerm = 1 initially as the first two digits in the output of the Fibonacci series. We use the for loop to print the firstTerm and secondTerm, add these two terms to compute nextTerm, and assign whatever value we got to nextTerm. We can also create a fibonacci sequence with a while loop. The program is essentially the same as the previous program. Although both programs work well, using a for loop would be better since the number of iterations from 1 to n is known.

import java.util.ArrayList;  
import java.util.HashMap;
import java.util.stream.Stream;

/* Objective will require changing to abstract class with one or more abstract methods below */
public class Fibo {
    String name;  // name or title of method
    int size;  // nth sequence
    int hashID;  // counter for hashIDs in hash map
    ArrayList<Long> list;   // captures current Fibonacci sequence
    HashMap<Integer, Object> hash;  // captures each sequence leading to final result

    /*
     Zero parameter constructor uses Telescoping technique to allow setting of the required value nth
     @param: none
     */
    public Fibo() {
        this(20); // telescope to avoid code duplication, using default as 20
    }

    /*
     Construct the nth fibonacci number
     @param: nth number, the value is constrained to 92 because of overflow in a long
     */
    public Fibo(int nth) {
        this.size = nth;
        this.list = new ArrayList<>();
        this.hashID = 0;
        this.hash = new HashMap<>();
        //initialize fibonacci and time mvc
        this.init();
    }

    /*
     This Method should be "abstract"
     Leave method as protected, as it is only authorized to extender of the class
     Make new class that extends and defines init()
     Inside references within this class would change from this to super
     Repeat process using for, while, recursion
     */
    protected void init() {
        this.name = "Stream";
        Stream.iterate(new long[]{0, 1}, f -> new long[]{f[1], f[0] + f[1]})
            .limit(this.size)
            .forEach(f -> this.setData(f[0]) );
    }

    /*
     Number is added to fibonacci sequence, current state of "list" is added to hash for hashID "num"
     */
    public void setData(long num) {
        list.add(num);
        hash.put(this.hashID++, list.clone());
    }

    /*
     Custom Getter to return last element in fibonacci sequence
     */
    public long getNth() {
        return list.get(this.size - 1);
    }

    /*
     Custom Getter to return last fibonacci sequence in HashMap
     */
    public Object getNthSeq(int i) {
        return hash.get(i);
    }

    /*
     Console/Terminal supported print method
     */
    public void print() {
        System.out.println("Init method = " + this.name);
        System.out.println("fibonacci Number " + this.size + " = " + this.getNth());
        System.out.println("fibonacci List = " + this.list);
        System.out.println("fibonacci Hashmap = " + this.hash);
        for (int i=0 ; i<this.size; i++ ) {
            System.out.println("fibonacci Sequence " + (i+1) + " = " + this.getNthSeq(i));
        }
    }

    /*
    Tester class method.  If this becomes abstract you will not be able to test it directly ...
    Change this method to  call "main" class of each of the extended classes
     */
    static public void main(String[] args) {
        Fibo fib = new Fibo();
        fib.print();
    }
}
Fibo.main(null);
Init method = Stream
fibonacci Number 20 = 4181
fibonacci List = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181]
fibonacci Hashmap = {0=[0], 1=[0, 1], 2=[0, 1, 1], 3=[0, 1, 1, 2], 4=[0, 1, 1, 2, 3], 5=[0, 1, 1, 2, 3, 5], 6=[0, 1, 1, 2, 3, 5, 8], 7=[0, 1, 1, 2, 3, 5, 8, 13], 8=[0, 1, 1, 2, 3, 5, 8, 13, 21], 9=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34], 10=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55], 11=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89], 12=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144], 13=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233], 14=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377], 15=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610], 16=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987], 17=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597], 18=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584], 19=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181]}
fibonacci Sequence 1 = [0]
fibonacci Sequence 2 = [0, 1]
fibonacci Sequence 3 = [0, 1, 1]
fibonacci Sequence 4 = [0, 1, 1, 2]
fibonacci Sequence 5 = [0, 1, 1, 2, 3]
fibonacci Sequence 6 = [0, 1, 1, 2, 3, 5]
fibonacci Sequence 7 = [0, 1, 1, 2, 3, 5, 8]
fibonacci Sequence 8 = [0, 1, 1, 2, 3, 5, 8, 13]
fibonacci Sequence 9 = [0, 1, 1, 2, 3, 5, 8, 13, 21]
fibonacci Sequence 10 = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34]
fibonacci Sequence 11 = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
fibonacci Sequence 12 = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89]
fibonacci Sequence 13 = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144]
fibonacci Sequence 14 = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233]
fibonacci Sequence 15 = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377]
fibonacci Sequence 16 = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610]
fibonacci Sequence 17 = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987]
fibonacci Sequence 18 = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597]
fibonacci Sequence 19 = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584]
fibonacci Sequence 20 = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181]
import java.util.ArrayList;  
import java.util.HashMap;
import java.util.stream.Stream;

/* Objective will require changing to abstract class with one or more abstract methods below */
public class Fibo {
    String name;  // name or title of method
    int size;  // nth sequence
    int hashID;  // counter for hashIDs in hash map
    ArrayList<Long> list;   // captures current Fibonacci sequence
    HashMap<Integer, Object> hash;  // captures each sequence leading to final result

    /*
     Zero parameter constructor uses Telescoping technique to allow setting of the required value nth
     @param: none
     */
    public Fibo() {
        this(20); // telescope to avoid code duplication, using default as 20
    }

    /*
     Construct the nth fibonacci number
     @param: nth number, the value is constrained to 92 because of overflow in a long
     */
    public Fibo(int nth) {
        this.size = nth;
        this.list = new ArrayList<>();
        this.hashID = 0;
        this.hash = new HashMap<>();
        //initialize fibonacci and time mvc
        this.init();
    }

    /*
     This Method should be "abstract"
     Leave method as protected, as it is only authorized to extender of the class
     Make new class that extends and defines init()
     Inside references within this class would change from this to super
     Repeat process using for, while, recursion
     */
    protected void init() {
        this.name = "Stream";
        Stream.iterate(new long[]{0, 1}, f -> new long[]{f[1], f[0] + f[1]})
            .limit(this.size)
            .forEach(f -> this.setData(f[0]) );
    }

    /*
     Number is added to fibonacci sequence, current state of "list" is added to hash for hashID "num"
     */
    public void setData(long num) {
        list.add(num);
        hash.put(this.hashID++, list.clone());
    }

    /*
     Custom Getter to return last element in fibonacci sequence
     */
    public long getNth() {
        return list.get(this.size - 1);
    }

    /*
     Custom Getter to return last fibonacci sequence in HashMap
     */
    public Object getNthSeq(int i) {
        return hash.get(i);
    }

    /*
     Console/Terminal supported print method
     */
    public void print() {
        System.out.println("Init method = " + this.name);
        System.out.println("fibonacci Number " + this.size + " = " + this.getNth());
        System.out.println("fibonacci List = " + this.list);
        System.out.println("fibonacci Hashmap = " + this.hash);
        for (int i=0 ; i<this.size; i++ ) {
            System.out.println("fibonacci Sequence " + (i+1) + " = " + this.getNthSeq(i));
        }
    }

    /*
    Tester class method.  If this becomes abstract you will not be able to test it directly ...
    Change this method to  call "main" class of each of the extended classes
     */
    static public void main(String[] args) {
        Fibo fib = new Fibo();
        fib.print();
    }
}
//Fibo.main(null);

public class FiboWhile extends Fibo { //extending the Fibo class 
    public void print() { //printing out all of the things needed for this new class
        System.out.println("Using Fibowhile " ); // title
        System.out.println("Init method = " + this.name); // init method name 
        System.out.println("fibonacci Number " + this.size + " = " + this.getNth()); // prints out the 20th term, list, and hashmap
        System.out.println("fibonacci List = " + this.list);
        System.out.println("fibonacci Hashmap = " + this.hash);

        int i = 0; // setting up int i as 0 initially
        while(i<this.size){ // while loop that uses .getNthSeq from parent class
            System.out.println("fibonacci Sequence " + (i+1) + " = " + this.getNthSeq(i));
            i++;
        }
    }
    static public void main(String[] args) { // setting the print for the FiboWhile and not Fibo
        Fibo fib = new FiboWhile();
        fib.print();
    }
}
FiboWhile.main(null); // running the FiboWhile class
Using Fibowhile 
Init method = Stream
fibonacci Number 20 = 4181
fibonacci List = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181]
fibonacci Hashmap = {0=[0], 1=[0, 1], 2=[0, 1, 1], 3=[0, 1, 1, 2], 4=[0, 1, 1, 2, 3], 5=[0, 1, 1, 2, 3, 5], 6=[0, 1, 1, 2, 3, 5, 8], 7=[0, 1, 1, 2, 3, 5, 8, 13], 8=[0, 1, 1, 2, 3, 5, 8, 13, 21], 9=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34], 10=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55], 11=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89], 12=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144], 13=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233], 14=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377], 15=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610], 16=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987], 17=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597], 18=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584], 19=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181]}
fibonacci Sequence 1 = [0]
fibonacci Sequence 2 = [0, 1]
fibonacci Sequence 3 = [0, 1, 1]
fibonacci Sequence 4 = [0, 1, 1, 2]
fibonacci Sequence 5 = [0, 1, 1, 2, 3]
fibonacci Sequence 6 = [0, 1, 1, 2, 3, 5]
fibonacci Sequence 7 = [0, 1, 1, 2, 3, 5, 8]
fibonacci Sequence 8 = [0, 1, 1, 2, 3, 5, 8, 13]
fibonacci Sequence 9 = [0, 1, 1, 2, 3, 5, 8, 13, 21]
fibonacci Sequence 10 = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34]
fibonacci Sequence 11 = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
fibonacci Sequence 12 = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89]
fibonacci Sequence 13 = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144]
fibonacci Sequence 14 = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233]
fibonacci Sequence 15 = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377]
fibonacci Sequence 16 = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610]
fibonacci Sequence 17 = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987]
fibonacci Sequence 18 = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597]
fibonacci Sequence 19 = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584]
fibonacci Sequence 20 = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181]

Fibonacci with Recursion (Extends)

To prevent repeating lines of code, we can use recursion to make our code and life simpler.

import java.util.ArrayList;  
import java.util.HashMap;
import java.util.stream.Stream;

/* Objective will require changing to abstract class with one or more abstract methods below */
public class Fibo {
    String name;  // name or title of method
    int size;  // nth sequence
    int hashID;  // counter for hashIDs in hash map
    ArrayList<Long> list;   // captures current Fibonacci sequence
    HashMap<Integer, Object> hash;  // captures each sequence leading to final result

    /*
     Zero parameter constructor uses Telescoping technique to allow setting of the required value nth
     @param: none
     */
    public Fibo() {
        this(20); // telescope to avoid code duplication, using default as 20
    }

    /*
     Construct the nth fibonacci number
     @param: nth number, the value is constrained to 92 because of overflow in a long
     */
    public Fibo(int nth) {
        this.size = nth;
        this.list = new ArrayList<>();
        this.hashID = 0;
        this.hash = new HashMap<>();
        //initialize fibonacci and time mvc
        this.init();
    }

    /*
     This Method should be "abstract"
     Leave method as protected, as it is only authorized to extender of the class
     Make new class that extends and defines init()
     Inside references within this class would change from this to super
     Repeat process using for, while, recursion
     */
    protected void init() {
        this.name = "Stream";
        Stream.iterate(new long[]{0, 1}, f -> new long[]{f[1], f[0] + f[1]})
            .limit(this.size)
            .forEach(f -> this.setData(f[0]) );
    }

    /*
     Number is added to fibonacci sequence, current state of "list" is added to hash for hashID "num"
     */
    public void setData(long num) {
        list.add(num);
        hash.put(this.hashID++, list.clone());
    }

    /*
     Custom Getter to return last element in fibonacci sequence
     */
    public long getNth() {
        return list.get(this.size - 1);
    }

    /*
     Custom Getter to return last fibonacci sequence in HashMap
     */
    public Object getNthSeq(int i) {
        return hash.get(i);
    }

    /*
     Console/Terminal supported print method
     */
    public void print() {
        System.out.println("Init method = " + this.name);
        System.out.println("fibonacci Number " + this.size + " = " + this.getNth());
        System.out.println("fibonacci List = " + this.list);
        System.out.println("fibonacci Hashmap = " + this.hash);
        for (int i=0 ; i<this.size; i++ ) {
            System.out.println("fibonacci Sequence " + (i+1) + " = " + this.getNthSeq(i));
        }
    }

    /*
    Tester class method.  If this becomes abstract you will not be able to test it directly ...
    Change this method to  call "main" class of each of the extended classes
     */
    static public void main(String[] args) {
        FiboRec recursion = new FiboRec();
        recursion.print();
     }
    
}

public class FiboRec extends Fibo { // extending FiboRec new class from parent class Fibo
    public int fibCalc (int i) { // using the recursion to produce Fibonacci sequence, the function fibCalc calls upon itself
        if (i <= 1) {
            return i;
        }
        else {
            return fibCalc(i-1) + fibCalc(i-2);
        }
    }

    public void print() {
        System.out.println("Init method = " + this.name);
        System.out.println("fibonacci Number " + this.size + " = " + this.getNth());
        System.out.println("fibonacci List = " + this.list);
        System.out.println("fibonacci Hashmap = " + this.hash);
        for (int i=0 ; i<this.size; i++ ) {
            System.out.println("fibonacci Sequence " + (i+1) + " = " + this.fibCalc(i));
        }
    }
    static public void main(String[] args) { // printing out this new class FiboRec
        Fibo recursion = new FiboRec();
        recursion.print();
     }
}
FiboRec.main(null);
Init method = Stream
fibonacci Number 20 = 4181
fibonacci List = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181]
fibonacci Hashmap = {0=[0], 1=[0, 1], 2=[0, 1, 1], 3=[0, 1, 1, 2], 4=[0, 1, 1, 2, 3], 5=[0, 1, 1, 2, 3, 5], 6=[0, 1, 1, 2, 3, 5, 8], 7=[0, 1, 1, 2, 3, 5, 8, 13], 8=[0, 1, 1, 2, 3, 5, 8, 13, 21], 9=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34], 10=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55], 11=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89], 12=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144], 13=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233], 14=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377], 15=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610], 16=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987], 17=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597], 18=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584], 19=[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181]}
fibonacci Sequence 1 = 0
fibonacci Sequence 2 = 1
fibonacci Sequence 3 = 1
fibonacci Sequence 4 = 2
fibonacci Sequence 5 = 3
fibonacci Sequence 6 = 5
fibonacci Sequence 7 = 8
fibonacci Sequence 8 = 13
fibonacci Sequence 9 = 21
fibonacci Sequence 10 = 34
fibonacci Sequence 11 = 55
fibonacci Sequence 12 = 89
fibonacci Sequence 13 = 144
fibonacci Sequence 14 = 233
fibonacci Sequence 15 = 377
fibonacci Sequence 16 = 610
fibonacci Sequence 17 = 987
fibonacci Sequence 18 = 1597
fibonacci Sequence 19 = 2584
fibonacci Sequence 20 = 4181