namespace IOCBeginnerGuide
{
  class Kid
  {
      private int _age;
      private string _name;

      public Kid(int age, string name)
      {
          _age = age;
          _name = name;
      }

      public override string ToString()
      {
          return "KID's Age: " + _age + ", Kid's Name: " + _name;
      }
  }
}

using System;

namespace IOCBeginnerGuide
{
  class Parent
  {
      private int _age;
      private string _name;
      private Kid _obj;

      public Parent(int personAge, string personName, int kidsAge, string kidsName)
      {
          _obj = new Kid(kidsAge, kidsName);
          _age = personAge;
          _name = personName;
      }

      public override string ToString()
      {
          Console.WriteLine(_obj);
          return "ParentAge: " + _age + ", ParentName: " + _name;
      }
  }
}

using System;

namespace IOCBeginnerGuide
{
  class Program
  {
      static void Main(string[] args)
      {
          Parent p = new Parent(35, "Dev", 6, "Len");
          Console.WriteLine(p);

          Console.ReadKey();
          Console.WriteLine("Press a key...");
      }
  }
}

KID's Age: 6, Kid's Name: Len
ParentAge: 35, ParentName: Dev

//IBuisnessLogic.cs
namespace IOCBeginnerGuide
{
  public interface IBuisnessLogic
  {
  }
}

//Kid.cs
namespace IOCBeginnerGuide
{
  class Kid : IBuisnessLogic
  {
      private int _age;
      private string _name;

      public Kid(int age, string name)
      {
          _age = age;
          _name = name;
      }

      public override string ToString()
      {
          return "KID's Age: " + _age + ", Kid's Name: " + _name;
      }
  }
}

//Parent.cs
using System;

namespace IOCBeginnerGuide
{
  class Parent
  {
      private int _age;
      private string _name;
      private IBuisnessLogic _refKids;

      public Parent(int personAge, string personName, IBuisnessLogic obj)
      {          
          _age = personAge;
          _name = personName;
          _refKids = obj;
      }

      public override string ToString()
      {
          Console.WriteLine(_refKids);
          return "ParentAge: " + _age + ", ParentName: " + _name;
      }
  }
}

//CIOC.cs
using System;

namespace IOCBeginnerGuide
{
  class CIOC
  {
      Parent _p;

      public void FactoryMethod()
      {
          IBuisnessLogic objKid = new Kid(12, "Ren");
          _p = new Parent(42, "David", objKid);
      }

      public override string ToString()
      {
          Console.WriteLine(_p);          
          return "Displaying using Constructor Injection";
      }
  }
}

//Program.cs
using System;

namespace IOCBeginnerGuide
{
  class Program
  {
      static void Main(string[] args)
      {
          CIOC obj = new CIOC();
          obj.FactoryMethod();
          Console.WriteLine(obj);

          Console.ReadKey();
          Console.WriteLine("Press a key...");
      }
  }
}

//Parent.cs
using System;

namespace IOCBeginnerGuide
{
  class Parent
  {
      private int _age;
      private string _name;

      public Parent(int personAge, string personName)
      {          
          _age = personAge;
          _name = personName;
      }

      public IBuisnessLogic RefKID {set; get;}

      public override string ToString()
      {
          Console.WriteLine(RefKID);
          return "ParentAge: " + _age + ", ParentName: " + _name;
      }
  }
}

//CIOC.cs
using System;

namespace IOCBeginnerGuide
{
  class CIOC
  {
      Parent _p;

      public void FactoryMethod()
      {
          IBuisnessLogic objKid = new Kid(12, "Ren");
          _p = new Parent(42, "David");
          _p.RefKID = objKid;
      }

      public override string ToString()
      {
          Console.WriteLine(_p);          
          return "Displaying using Setter Injection";
      }
  }
}