Stack is a linear data structure in which the element inserted last is the element to be deleted first.
It is also called Last In First Out (LIFO).
In a stack, the last inserted element is at the top.
Operations of the stack are
push(): inserts an element into the stack at the end
pop(): deletes and returns the last inserted element from the stack
peek(): returns the last inserted element
After inserting three elements in the stack, it will look like this:
After performing the pop operation twice, the stack elements will look like:
def push(stack,element): """insertion of 'element' into the stack""" stack.append(element) def pop(stack): """deletes and returns the last inserted element""" if len(stack)==0: print("stack underflow") quit() return stack.pop() def peek(stack): """returns the last inserted element""" if len(stack)==0: print("stack is empty") return -1 return stack[-1]
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