Question

The Fibonacci series: 0, 1, 1, 2, 3, 5, 8, 13, 21, has as its first 2 values, 0 and 1; each successive value if then calculated as the sum of the previous two values. The first element in the series is the 0'th element, thus the value 8 is element 6 of the series. The n'th element of the series, written as fib(n), is thus defined as: n if n = 0 or n = 1 fib(n-1) + fib(n-2) Write the int-valued method fib, that takes a single int parameter (say n), and recursively calculates and then returns the n'th element of the Fibonacci series.

Answer 1

Answer:

// Code in C++.

// headers

#include <bits/stdc++.h>

using namespace std;

// recursive function to find nth term of Fibonacci series

int fib(int num)

{

   // base case

    if (num == 0||num==1)

         return num;

    else

    // recursive call

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

}

// driver function

int main()

{

   // variables

int num, term;

    cout << "Enter the position value : ";

    // read the value of num

    cin >> num;

    // call the function

    term = fib(num);

    // print the nth term

    cout <<"The "<<num<< "th Fibonacci number is: " <<term<<endl;

return 0;

}

Explanation:

Read the value of term number from user and assign it to variable "num".Then call the recursive function fib() with parameter "num".In this function, if num=1 or  num=0 (base case for recursive call) then function will return the value of num. otherwise it will recursively call itself and find the nth term of the Fibonacci series.

Output:

Enter the position value : 6                                                                                              

The 6th Fibonacci number is: 8