Fibonacci sequence [ iterative/recursive/cached] with timers.

gistfile1.java

package programs;

public class Fibonacci {

  public static int fibrecursive(int n) {
		if(n<=1){
			return n;
		}
		return fibrecursive(n-1)+fibrecursive(n-2);
	}
	
	public static void fibhelper(int n){
		
		for(int i = 0;i < n;++ i)
		{
			System.out.print(fibrecursive(i)+" ");
			// fibrecursive(i);
		}
	}
	
	/**
	 * fibonacci sequence with caching implemented
	 */
	static int arr[] = new int[100];
	public static void fibWithCaching(int n) {
		int j=0;
		arr[0]=0;
		arr[1]=1;
		for(j=0; j<n; j++)
		{
			System.out.print(arr[j] + " ");
		}
		
		try{
			arr[n] = arr[j-1] + arr[j-2];
			System.out.println();
		}catch(IndexOutOfBoundsException e){
			// System.out.println("exception");
		}
	}
	
	/*non recursive fibonacci function*/
	public static void fibIterative(int n)
	{
		int prev = -1;
		int next = 1;
		int sum;
		int i;
		
		for(i = 0;i < n;++ i)
		{
			sum = next + prev;
			prev = next;
			next = sum;
			arr[i] = next;
			System.out.print(next + " ");
			if(i == n-1){
				System.out.println();
			}
		}
	}

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		
		int limit = 20;
		long starttime0 = System.nanoTime();
		for(int i = 0;i <= limit;++ i)
		{
			fibhelper(i);
			System.out.println();
		}
		long estimatedTime0 = System.nanoTime() - starttime0;
		System.out.println(estimatedTime0);
		
		long starttime1 = System.nanoTime();
		for(int i = 0;i <= limit;++ i)
		{
			fibIterative(i);
		}
		long estimatedTime1 = System.nanoTime() - starttime1;
		System.out.println(estimatedTime1);
		
		long starttime2 = System.nanoTime();
		for(int i = 0;i <= limit;++ i)
		{
			fibWithCaching(i);
		}
		long estimatedTime2 = System.nanoTime() - starttime2;
		System.out.println(estimatedTime2);
	}

}