Hi can anyone please explain me what is companion object and how it is related to static members and static methods( I know C++)

A companion object is a singleton (like normal objects in Kotlin). Additionally the methods and properties in a companion object can also be accessed by just the class's name. But the companion object can be passed around (it's an actual instance), it can implement interfaces, etc.

Like static members are shared by each object so does this happen with companion object

Since objects are singletons, you will have a similar effect.

Lets say there is count property in companion object will there be same copy of count for each object

the property does not exist on objects of the class. It only exists on the companion object

pardon me

Example:

class Foo(val instanceProp: Int) {
   companion object {
      var sharedProp: Int = 3
   }
}
val instance = Foo(5)
println(instance.instanceProp) // 5
printn(Foo.sharedProp) // 3

lets say I introduce a method in companion object to increment sharedProp by 1 whenever a new object is created ,Is it possible

Yes, you could do so:

class Foo {
  init {
    // short for: Companion.instanceCount++
    instanceCount++ 
  }
  companion object {
    var instanceCount: Int = 0
  }
}

So basically what you are saying is that companion object's members and methods have one copy for all objects and methods could be called without any object

They don't have a copy. The companion object is a singleton (only once instance of it exists). Therefor all the properties in it also only exist once.

anything i miss?

First start with normal objects:

class Foo {
   init {
      MyObject.instanceCount++
   }
}

object MyObject {
   var instanceCount = 0
}

Ok I think I have understood please add anything which may have been missed in discussion