A method to calculate the value of a continued fraction

ContinuedFractions.java

public class ContinuedFractions {
	public static void main(String[] args) {
		double[] e_cf = {2,1,2,1,1,4,1,1,6,1,1,8,1,1,10,1,1,12,1,1,14};
		
		System.out.println(cf(e_cf));	
		System.out.println(Math.E);
	}
	// optionally pass the index value and do not copy the tail array every time
	public static double cf(double... d) {
		if (d.length == 0) return 0;
		if (d.length == 1) return d[0];
		return d[0] + 1 / cf(tail(d));
	}
	
	public static double[] tail(double... array) {
		
		if (array.length <= 1) throw new Error("This array has no tail");
		
		double[] tail = new double[array.length - 1];
		for (int i = 1; i < array.length; i++) {
			tail[i - 1] = array[i]; 
		}
		return tail;
	}
}