Exercises 1

Fibonacci

The Fibonacci numbers 1, 1, 2, 3, 5, 8, 13 ... are defined by recursion like this:


	a(n) =		1				for n=1, n=2
	
	a(n) =		a(n-1) + a(n-2)			for n>2

Write a function to calculate the n’th Fibonacci number.

First - sketch your function on paper.
Next – implement a program to test it.
Last – make a drawing to show the function-calls involved in calculating the seventh Fibonacci number.

See Solution:


function FibonacciRecusive(n){
	if(n===1 || n===2){
		return 1;
	}else{
		return FibonacciRecusive(n-1)+FibonacciRecusive(n-2);
	}
}
function Fibonacci(n){
	var i, num1 = 1, num2 = 1, nextnum;
	for(i=2;i<n;i++){
		nextnum = num1+num2;
		num1 = num2;
		num2 = nextnum;
	}
	return num2;
}

Result :