std::stack<T,Container>::top

 

C++

Language

Standard Library Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Input/output library

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Regular expressions library (C++11)

Atomic operations library (C++11)

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Technical Specifications

 

Containers library

array (C++11)

vector

deque

forward_list (C++11)

list

set

multiset

map

multimap

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

stack

queue

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span (C++20)

 

std::stack

Member functions

stack::stack

stack::~stack

stack::operator=

Element access

stack::top

Capacity

stack::empty

stack::size

Modifiers

stack::push

stack::emplace

stack::pop

stack::swap

Deduction guides(C++17)

 

reference top();
const_reference top() const;

Returns reference to the top element in the stack. This is the most recently pushed element. This element will be removed on a call to pop(). Effectively calls c.back().

Parameters

(none)

Return value

Reference to the last element

Complexity

Constant

Example

Run this code

#include <stack>
#include <iostream>
 
int main()
{
    std::stack<int>   s;
 
    s.push( 2 );
    s.push( 6 );
    s.push( 51 );
 
    std::cout << s.size() << " elements on stack\n";
    std::cout << "Top element: "
	      << s.top()         // Leaves element on stack
	      << "\n";
    std::cout << s.size() << " elements on stack\n";
    s.pop();
    std::cout << s.size() << " elements on stack\n";
    std::cout << "Top element: " << s.top() << "\n";
 
    return 0;
}

Output:

3 elements on stack
Top element: 51
3 elements on stack
2 elements on stack
Top element: 6

See also

push	inserts element at the top (public member function)
pop	removes the top element (public member function)