递归的小练习，

    public static void main(String[] args) {
        System.out.println(sum(10));
        System.out.println(mul(10));
        System.out.println(tu(3));
        getInFo("D:\\");

    }

    //递归累和
    public static int sum(int num) {
        if (num==1) {
            return 1;
        }else {
            return sum(num-1)+num;
        }
    }

    //递归累乘
    public static int mul(int num) {
        if (num==1) {
            return 1;
        }else {
            return mul(num-1)*num;
        }
    }

    //斐波那契兔子递归
    public static int  tu(int num) {
        if (num==1 || num ==2) {
            return 1;
        }else {
            return tu(num-1)+tu(num-2);
        }
    }

    //递归遍历输出xx文件夹内的文件的绝对路径
    public static void getInFo(String path) {
        File myfile = new File(path);
        File[] files = myfile.listFiles();
        for (File file : files) {
            if (file.isFile()) {
                System.out.println(file.getAbsolutePath());
            }else {
                System.out.println(file.getAbsolutePath());
                getInFo(file.getAbsolutePath());
            }
        }
    }复制