Fibonacci

For Loops with extends

// for loops

class Fibonacci {
    ArrayList<Integer> sequence;
    int steps;

    public Fibonacci() {
        sequence = new ArrayList<Integer>();
        sequence.add(0);
        sequence.add(1);   
        this.getInput();
        this.generateSequence();
    }
    

    public void getInput() {
        Scanner input = new Scanner(System.in);
        
        System.out.println("How many terms do you want to generate? (greater than 2)");
        steps = input.nextInt();
        System.out.println(steps);
    }

    public void generateSequence() {
        for(int i = 2; i<steps; i++) {
            sequence.add(sequence.get(i-2) + sequence.get(i-1));
        }
        System.out.println(sequence);
    }
    
    public static void main(String[] args)  {
        new Fibonacci();
    }
}

Fibonacci.main(null);

// for loop with extends
class Fibo extends Fibonacci {
    ArrayList<Integer> sequence;
    int steps;
    
    public Fibo() {
        // inherits properties of for loop, so we don't have to rewrite functions
        super();
    }    
    public static void main(String[] args)  {
        System.out.println("\nUsing extends:");
        new Fibo();
    }
}

Fibo.main(null);

How many terms do you want to generate? (greater than 2)
8
[0, 1, 1, 2, 3, 5, 8, 13]

Using extends:
How many terms do you want to generate? (greater than 2)
8
[0, 1, 1, 2, 3, 5, 8, 13]

While Loop

class Fibonacci {
    ArrayList<Integer> sequence;
    int steps;

    public Fibonacci() {
        sequence = new ArrayList<Integer>();
        sequence.add(0);
        sequence.add(1);   
        this.getInput();
        this.generateSequence();
    }
    

    public void getInput() {
        Scanner input = new Scanner(System.in);
        
        System.out.println("How many terms do you want to generate? (greater than 2)");
        steps = input.nextInt();
        System.out.println(steps);
    }

    public void generateSequence() {
        int i = 2;
        while(i<steps) {
            sequence.add(sequence.get(i-2) + sequence.get(i-1));
            i++;
        }
        System.out.println(sequence);
    }
    
    public static void main(String[] args)  {
        new Fibonacci();
    }
}

Fibonacci.main(null);

How many terms do you want to generate? (greater than 2)
8
[0, 1, 1, 2, 3, 5, 8, 13]

Recursion

class Fibonacci {
  ArrayList<Integer> sequence;
  int steps;

  public Fibonacci() {
      sequence = new ArrayList<Integer>();
      sequence.add(0);
      sequence.add(1);   
      this.getInput();
      this.generateSequence();
  }
  

  public void getInput() {
      Scanner input = new Scanner(System.in);
      
      System.out.println("How many terms do you want to generate? (greater than 2)");
      steps = input.nextInt();
      System.out.println(steps);
  }

  // recursive method to generate term i of fibonacci sequence
  public int generateTerm(int i) {
      if(i<=1) {
        return i;
      }
      return generateTerm(i-2) + generateTerm(i-1);
  }

  // adds terms of fibonacci to sequence
  public void generateSequence() {
    for(int i = 2; i<steps; i++) {
        sequence.add(this.generateTerm(i));
    }
    System.out.println(sequence);
  }
  
  public static void main(String[] args)  {
      new Fibonacci();
  }
}

Fibonacci.main(null);

How many terms do you want to generate? (greater than 2)
8
[0, 1, 1, 2, 3, 5, 8, 13]