Final answer:
The code provided is an implementation of a stack using a class template in C++.
Step-by-step explanation:
The subject of this question is Computers and Technology. The code provided is an implementation of a stack using a class template in C++. The class template Stack has a private data member top that keeps track of the top index of the stack and an array arr to store the elements of the stack.
The class template provides member functions such as push() to add elements to the stack, pop() to remove elements from the stack, and isEmpty() to check if the stack is empty.
The main function demonstrates the usage of the class template by creating an instance of Stack, pushing elements onto the stack, and then popping elements from the stack to display them.