Stack

The std::stack follows the LIFO principle (Last In First Out). The stack sta, which needs the header <stack>, has three special methods.

With sta.push(e) you can insert a new element e at the top of the stack, remove it from the top with sta.pop() and reference it with sta.top(). The stack supports the comparison operators and knows its size. The operations of the stack have constant complexity.

std::stack

// stack.cpp
...
#include <stack>
...
std::stack<int> myStack;

std::cout << myStack.empty() << std::endl;   // true
std::cout << myStack.size() << std::endl;    // 0

myStack.push(1);
myStack.push(2);
myStack.push(3);
std::cout << myStack.top() << std::endl;     // 3

while (!myStack.empty()){ 
  std::cout << myStack.top() << " ";
  myStack.pop();
}                                            // 3 2 1

std::cout << myStack.empty() << std::endl;   // true
std::cout <&lt...