itech9

from
http://www.csd.uwo.ca/courses/CS1027b/code/FibonacciDemo.java

    /** Method to calculate the nth Fibonacci number iteratively.
     * @param n
     * @return nth Fibonacci number
     * precondition: n >= 1
     */
    public static long ifib(long n) {
        if (n &lt 2) {
            return 1;
        } else {
            long prev = 1, current = 1, next = 0;
            for (long i = 3; i &lt= n; i++) {
                next = prev + current;
                prev = current;
                current = next;
            }
            return next;
        }
    }

from http://javadecodedquestions.blogspot.com/2013/01/java-interviews-frequently-asked-puzzles.html

public class FibonacciNumber {
  public static int fibonacci(int n) {
   if (n < 2) {
    return n;
   }
   else {
    return fibonacci(n - 1) + fibonacci(n - 2);
   }
  }
}

from http://stackoverflow.com/questions/8965006/java-recursive-fibonacci-sequence

public int fibonacci(int n)  {
    if(n == 0)
        return 0;
    else if(n == 1)
      return 1;
   else
      return fibonacci(n - 1) + fibonacci(n - 2);
}