How is the stack and stack pointer work?

A stack is a data structure in which last item inserted is taken out first . That's why they are known as LIFO (last in first out). Inserting an item in stack is termed as push and taking an item out from stack I s termed as pop. Stack pointer is the pointer that points to the top of the stack or that points the item at the top of the stack and help in adding or deleting the item from the top of stack.