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

 

C++

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Containers library

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array (C++11)

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std::stack

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stack::empty

stack::size

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stack::push

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Non-member functions

operator==operator!=operator<operator>operator<=operator>=operator<=> (C++20)

std::swap (C++11)

Deduction guides(C++17)

 

bool empty() const;		(until C++20)
[[nodiscard]] bool empty() const;		(since C++20)

Checks if the underlying container has no elements, i.e. whether c.empty().

Parameters

(none)

Return value

true if the underlying container is empty, false otherwise

Complexity

Constant

Example

Run this code

#include <algorithm>
#include <iostream>
#include <stack>
 
int main()
{
    std::cout << std::boolalpha;
 
    std::stack<int> container;
 
    std::cout << "Initially, container.empty(): " << container.empty() << '\n';
 
    container.push(42);
    std::cout << "After adding elements, container.empty(): " << container.empty() << '\n';
}

Output:

Initially, container.empty(): true
After adding elements, container.empty(): false

See also

size	returns the number of elements (public member function)