（斐波那契总结）Write a method to generate the nth Fibonacci number (CC150 8.1)

根据CC150的解决方式和Introduction to Java programming总结：

使用了两种方式，递归和迭代

CC150提供的代码比较简洁，不过某些细节需要分析。

现在直接运行代码，输入n（其中用number代替，以免和方法中的n混淆）的值，可以得出斐波那契数。

代码如下：

/*  CC150 8.1
    Write a method to generate the nth Fibonacci number
    Author : Mengyang Rao
    note : Use two methods ,Iteration and Recursion
    Date : 2015-02-25 23:56:00
*/


import java.util.Scanner;
public class TestFibonacci {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.print("Please enter n :");
        int number = input.nextInt();
        System.out.println("The Iteration number is : " + fibonacci(number) + "\n n value is : " + number);
        System.out.println("The Recursion number is : " + fibo(number) + "\n n value is : " + number);
    }
// Version: Recursion
    public static long fibo(long n ) {
    if(n == 0) 
        return 0;
    else if (n == 1)
        return 1;
    else if (n > 1)
        return fibo(n - 1) + fibo(n - 2);
    else 
        return -1;
}
//  Version: Iteration
    public static long fibonacci(long n) {
        int a = 0, b = 1;
        if (n < 0) 
            return -1;
        else if (n == 0)
            return 0;
        for (int i = 3; i <= n; i++) {
            int c = a + b;
            a = b;
            b = c;
        }
        return b;
    }
}