Anatomy of std::stack Container Adapter

std::stack is a container adapter in C++ that provides a Last-In, First-Out (LIFO) data structure, commonly known as a stack. It abstracts away the underlying container implementation, allowing developers to focus on the logical operations of a stack without delving into the details of memory management.

Characteristics:

• LIFO Behavior: Follows the Last-In, First-Out order for elements.
• Adapter Nature: Built on top of other STL containers, such as std::deque, std::list, or std::vector.

Creation of std::stack:

Creating a std::stack involves declaring an instance and specifying the underlying container type, which defaults to std::deque:

#include <stack>

std::stack<int> myStack;  // Default underlying container is std::deque<int>
std::stack<int, std::vector<int>> myVectorStack;  // Using std::vector<int> as the underlying container

Functions

1. Element Access Functions:

top():

• Returns a reference to the top element of the stack.

Example:

std::stack<int> myStack;
int topElement = myStack.top();

2. Capacity Functions:

empty():

• Checks if the stack is empty.

Example:

std::stack<int> myStack;
bool isEmpty = myStack.empty();

size():

• Returns the number of elements in the stack.

Example:

std::stack<int> myStack;
size_t sizeOfStack = myStack.size();

3. Modifiers Functions:

push(const T& value):

• Adds an element to the top of the stack.

Example:

std::stack<int> myStack;
myStack.push(42);

pop():

• Returns the top of element from the stack.

Example:

std::stack<int> myStack;
myStack.pop();