递归练习题

Posted 2022-09-01 lsswudi

不死神兔

package com.liushuaishuai;
/*
不死神兔递归
 */

public class DiGuiDemo 
    public static void main(String[] args) 
        System.out.println(f(20));
    

    public static int f(int n) 
        if (n == 1 || n == 2) 
            return 1;
         else 
            return f(n - 1) + f(n-2);
        


    

 求阶乘

package com.liushuaishuai;

public class DiGuiDemo02 
    public static void main(String[] args) 
        System.out.println(Factorial(4));
    

    public static int Factorial(int n) 
        if (n == 1) 
            return 1;
         else 
            return n * Factorial(n - 1);
        
    

 遍历目录

package com.liushuaishuai;

import java.io.File;

public class DiGuiDemo03 
    public static void main(String[] args) 
        File srcFile = new File("C:\\\\java");

                //调用方法
                getFile(srcFile);
    

    public static void getFile(File file) 
        //获取给定目录下所有的文件或目录
        File[] filearray = file.listFiles();
        if (filearray != null) 
            for (File s : filearray) 
                //判断File对象是否是目录
                if(s.isDirectory()) 
                    getFile(s);
                    //是：递归调用
                 else 
                    System.out.println(s.getAbsolutePath());