Stack

Creating a stack:

Stack<return_type> stack;

will create a stack that stores elements of type <return_type>. The stack follows the Last In, First Out (LIFO) principle, meaning the last element added is the first one to be removed.

Functions:

Function	Description	O notation
push(x)	Adds the element x of type <return_type> to the stack.	O(1)
pop()	Removes the lastly added element to the stack (if any) and returns it.	O(1)
top()	Return the lastly added element to the stack (if any).	O(1)
empty()	Check whether the stack is empty, returns a boolean.	O(1)

Example use case:

Stack<int> stack;
stack.push(10);
stack.push(20);
stack.push(30);
std::cout << "Top element: " << stack.top() << std::endl; // Top element: 30
std::cout << "Popped: " << stack.pop() << std::endl; // Popped: 30
std::cout << "Stack empty? " << (stack.empty() ? "Yes" : "No") << std::endl; // Stack empty? No