递归与循环

public class Exam9_Fibonacci {
    public static void main(String[] args) {
        int n=10;    
        //递归
        long start = System.currentTimeMillis();            
        System.out.println("当n= "+n+" 时的结果是 "+ Fibonacci(n));
        long end = System.currentTimeMillis();
        System.out.println("递归方式：");
        System.out.println("运行的时间是"+(end-start)+"ms");
        
        //循环
        long start1 = System.currentTimeMillis();    
        System.out.println("\n循环方式：");
        Circulation(n);
        long end1 = System.currentTimeMillis();
        System.out.println("运行的时间是"+(end1-start1)+"ms");
    }
    

    //利用递归方式
    private static long Fibonacci(int n) {
        if(n<=0)
            return 0;
        if(n==1)
            return 1;        
        return Fibonacci(n-1) + Fibonacci(n-2);
    }
    
    //利用循环方式
    private static long Circulation(int n) {
        
        if(n<=0)
            return 0;
        if(n==1)
            return 1;
        
        long finSOne= 0;
        long finSTwo = 1;
        long fibN= 0;
        
        for(int i=2;i<=n;i++)
        {
            fibN = finSOne+finSTwo;
            finSOne = finSTwo;
            finSTwo = fibN;        
        }
        return fibN;
    }
}