Resolve the bug in the c# code

There are a couple of ways you could do this. The first is to pass an object:

public void Hit(object x)
   {
   }

But this has big problems - you have to check explicitly what type teh incoming parameter is and deal with it appropriately:

public void Hit(object x)
   {
   Cat c = x as Cat;
   if (c != null)
      {
      c.Run();
      }
   Dog d = x as Dog;
   if (d != null)
      {
      d.Run();
      }
   }

That isn't a nice approach, and it's difficult to expand, and prone to errors.

The better approach would be to create a Base Class:

public abstract class Animal
    {
    public abstract void Run();
    }

(We declare it as abstract so that you can't create an instance of it)
And then derive each animal class from that:

public class Dog : Animal
    {
    public override void Run()
        {
        Console.WriteLine("Dog Runs");
        }
    }
public class Cat : Animal
    {
    public override void Run()
        {
        Console.WriteLine("Cat Runs");
        }
    }

(The override keyword tells the system this replaces the base class version with a Cat or Dog specific version)
You can then declare your Hit method to take an Animal, and the system will sort out which Run method to use:

public class Human
    {
    public void Hit(Animal x)
        {
        x.Run();
        }
    }

HI

You should specify a Type in the parameter..
if u specify as Dog , u can be able to access only Dog Class Run Method, not the Cat class and vice versa,
To fix this issue u have to create an interface with the Common method as Run()
and implement the interface in the DOG and Cat Classes.
then you try to call the Human class Run method with any Animals which is implemented by IAnimal Interface..

If it is an Interview question, the answer is the above.



Try like this..

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace CatDog
{

    class Program
    {
        static void Main(string[] args)
        {
            Dog dog = new Dog();
            Cat cat = new Cat();
            Human human = new Human();
            human.Hit(cat);
            human.Hit(dog);
            Console.ReadLine();
        }
    }

    interface IAnimal { void Run();}
    class Dog : IAnimal
    {
        public   void Run()
        {
            Console.WriteLine("Dog Runs");
        }
    }
    class Cat : IAnimal
    {
        public   void Run()
        {
            Console.WriteLine("Cat Runs");
        }
    }

    class Human
    {
        public void Hit(IAnimal x)
        {

            x.Run();
        }
    }
}