面试总结

Posted 2020-11-19 2186009311cff

 

题一：

程序设计: 猫大叫一声，所有的老鼠都开始逃跑，主人被惊醒。(C#语言)
要求：  
            <1>.构造出Cat、Mouse、Master三个类，并能使程序运行
            <2>从Mouse和Master中提取抽象
            <3>联动效应，只要执行Cat.Cryed()就可以使老鼠逃跑，主人惊醒。

using System;
using System.Collections;
using System.Collections.Generic  ;

namespace gtkTest
{
    public class ObserverClass
    {
        public ObserverClass ()
        {
            
        }
        public  static void  ObserverFun ()
        {
            Cat cat = new Cat();
            Mouse mouse1 = new Mouse("mouse1", cat);
            Mouse mouse2 = new Mouse("mouse2", cat);
            Master master = new Master(cat);
            cat.Cry();
        }
        public interface Observer
        {
            void Response();    //观察者的响应，如是老鼠见到猫的反映
        }
        public interface Subject
        {
            void AimAt(Observer obs);  //针对哪些观察者，这里指猫的要扑捉的对象---老鼠
        }
        public class Mouse : Observer
        {
            private string name;
            public Mouse(string name, Subject subj)
            {          
                this.name = name;
                subj.AimAt(this);
            }

            public void Response()
            {
                Console.WriteLine(name + " attempt to escape!");
            }
        }
        public class Master : Observer
        {  
            public Master(Subject subj)
            {          
                subj.AimAt(this);
            }

            public void Response()
            {
                Console.WriteLine("Host waken!");
            } 
        }

        public class Cat : Subject
        {
            private ArrayList observers;
            public Cat()
            {  
                this.observers = new ArrayList();
            }
            public void AimAt(Observer obs)
            {
                this.observers.Add(obs);
            }
            public void Cry()
            {
                Console.WriteLine("Cat cryed!");
                foreach (Observer obs in this.observers)
                {
                    obs.Response();
                }
            }
        }


    }
}

//2

using System;

namespace gtkTest
{
    public class ObserverDeleClass
    {
        public ObserverDeleClass ()
        {
            
        }
        public static  void ObserverDeleFun ()
        {
            Cat cat = new Cat();
            Mouse mouse1 = new Mouse("ObserverDelemouse1", cat);
            Mouse mouse2 = new Mouse("ObserverDelemouse2", cat);
            Master master = new Master(cat);
            cat.Cry();
        }
        //---------------------------------------------------------------------------------------------
        //设计方法二: 使用event -- delegate设计..
        public delegate void SubEventHandler();
        public abstract class Subject
        {
            public event SubEventHandler SubEvent;
            protected void FireAway()
            {
                if (this.SubEvent != null)
                    this.SubEvent();
            }  
        }
        public class Cat : Subject
        { 
            public void Cry()
            {
                Console.WriteLine("ObserverDelecat cryed.");
                this.FireAway();
            }
        }
        public abstract class Observer
        {
            public Observer(Subject sub)
            {
                sub.SubEvent += new SubEventHandler(Response);
            }
            public abstract void Response();   
        }
        public class Mouse : Observer
        {
            private string name;
            public Mouse(string name, Subject sub) : base(sub)
            {  
                this.name = name;
            }
            public override void Response()
            {
                Console.WriteLine(name + " attempt to escape!");
            }
        }
        public class Master : Observer
        {
            public Master(Subject sub) : base(sub){}
            public override void Response()
            {
                Console.WriteLine("ObserverDelehost waken");
            }
        }

    }
}
//3

gtkTest.ObserverDeleClass.ObserverDeleFun();

        gtkTest.ObserverClass.ObserverFun ();

　　

 

 

参考：　https://blog.csdn.net/hunterxray/article/details/1532674

题二：

一列数的规则如下: 1、1、2、3、5、8、13、21、34......  求第30位数是多少， 用递归算法实现

public class MainClass   
    {   
        public static void Main()     
        {   
            Console.WriteLine(Foo(30));   
        }   
  
        public static int Foo(int i)   
        {   
            if (i <= 0)   
                return 0;   
            else if(i > 0 && i <= 2)   
                return 1;   
            else return Foo(i -1) + Foo(i - 2);   
        }   
    }   

参考：https://blog.csdn.net/zhangzuqing/article/details/20208385

 

题三

 

 

注意：