What is a stack in c plus plus?

You don't say which operation you wish to perform, however a stack has relatively few members:

construct: e.g. default and copy (C++11 includes move construct)

operator=: copy assignment (C++11 includes move assignment)

empty: test whether the stack is empty or not

pop: extract the top element from the stack

push: insert an element on top of the stack

size: return the size of the stack, count of elements

top (return the top element)

Additional members since C++11:

emplace: construct and push a new element from argument

swap: exchange elements with another stack

Non-member operator overloads are limited to the standard relational operators (e.g. ==, !=, <, <=, > and >=).

Stacks are typically used in backtracking algorithms because the last element pushed becomes the top element and is therefore the first element to be popped. Usually referred to as a LIFO (last in first out) sequence.

An example usage of a stack:

#include<iOStream>

#include<stack>

#include<string>

#include<cassert>

int main ()

{

std::stack<std::string> mystack;

assert (mystack.empty());

mystack.push ("First element");

mystack.push ("Second element");

assert (mystack.size()==2);

std::cout << "mystack contains:\n";

while (!mystack.empty())

{

std::cout << mystack.top() << '\n';

mystack.pop();

}

}