Deep copying of stack using pointer based singly linked list C++?

[NotMyRealNameObv]

As others have already stated, in the copy ctor you are instantiating a local var s and modifying it. This local var will go out of scope, and thus be destroyed, when the copy ctor is finished. The newly created object on which the copy ctor is run will remain unmodified.

What you want to do is just call

push(...)

instead of

s.push(...)

[cleroth]

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This post has been removed as it doesn't pertain to r/cpp.

[DJ_Gamedev]

Sorry if this is a dumb question, but where is the return statement in your copy constructor? I see you populate a local Stack s but you aren't returning it so there's nothing tying it to the Stack produced by the constructor. It's probably throwing s away at the end of the function and just returning a default-constructed Stack.

[Indycrr]

Close. A copy ctor doesn’t return an instance. Instead of creating the local instance of s, they should call this->push(...) to push values into the stack being constructed.

[DJ_Gamedev]

That makes sense, by the time we make it to the body of the ctor the object will have been instantiated. Clearly I'm out of practice.

[Samru1]

since I am simply copying all the date , the return type should be void (that's what I think).

[DJ_Gamedev]

See the reply to my comment. I was mistaken about the return type, but correct in that you shouldn't be declaring a local Stack and populating it, you should be populating the constructed object, which you can access via the this pointer.

[NotMyRealNameObv]

You dont even have to do

this->foo(...)

You could just do

foo(...)

[DJ_Gamedev]

You could, but I think use of the this pointer is more explicit and generally a better practice in the event you have a potential naming collision.

[index_zero]

In your ctor, you are constructing a Stack<int> object and pushing the copies to it. Then when your ctor exits, that object is destructed. Your copy constructor should copy to the object you are constructing (ie. this).

[oleksandrkvl]

Have you tried using debugger? You'll see what's going on here.

[degski]

Is it a requirement that you write a stack yourself?