Answer 1

Next time, please provide a minimal example that shows the problem.
No need for the wall of code. It'll also increase the chance of getting a useful reply
Probably the easiest way to check if 2 classes are the same is to give the base class an additional variable called "ID" or something, preferably of an integral type, and initialize it to a value that is unique to each class.
For example the Item class' constructor would initialize this variable to 0,
class Food to 1 and class Tool to 2.
Then as an additional check you simply do
id == obj.id; // True if they are the same class, false otherwise.
( No need for this->, people usually use prefixes for member variables, like id => m_id )
At least, this is what I think you mean. :)
Also,
I recommend marking your Item's destructor as virtual.
and in addition to AZTECCO's reply:
https://isocpp.org/wiki/faq/const-correctness

Answer 2

bool operator ==(const Item& obj)
{
return ( this->name == obj.name &&
this->price == obj.price &&
this->weight == obj.weight );
}

Answer 3

Thank you Dennis for clarification about "const" !
And for this-> .. some people still use it for readability, I prefer to not use it too.
The same applies to return (....);
()are not needed to make it work

Answer 4

AZTECCO Yeah, it's not that much of an issue if you use this-> AND a prefix.
But only using this-> can cause annoying bugs when you inevitably forget it and 2 variable names match.
Can't get that issue if you used a prefix.

Answer 5

You could look into typeid: https://en.cppreference.com/w/cpp/language/typeid

Answer 6

Class classname : public derived classname