（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;

    }

}