std::inplace_vector<T,N>::operator[]

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (C++17)

Regular expressions library (C++11)

Concurrency support library (C++11)

Execution support library (C++26)

Technical specifications

Symbols index

External libraries

 

Containers library

Sequence

array (C++11)

vector

vector<bool>

inplace_vector (C++26)

deque

forward_list (C++11)

list

Associative

set

multiset

map

multimap

Unordered associative

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

Adaptors

stack

queue

priority_queue

flat_set (C++23)

flat_multiset (C++23)

flat_map (C++23)

flat_multimap (C++23)

Views

span (C++20)

mdspan (C++23)

Tables

Iterator invalidation

Member function table

Non-member function table

 

std::inplace_vector

Member types
Member functions
inplace_vector::inplace_vector inplace_vector::~inplace_vector    inplace_vector::operator= inplace_vector::assign inplace_vector::assign_range Size and capacity inplace_vector::empty inplace_vector::size inplace_vector::max_size inplace_vector::capacity inplace_vector::resize inplace_vector::reserve inplace_vector::shrink_to_fit Iterators inplace_vector::begininplace_vector::cbegin inplace_vector::endinplace_vector::cend inplace_vector::rbegininplace_vector::crbegin inplace_vector::rendinplace_vector::crend	Element access inplace_vector::at inplace_vector::operator[] inplace_vector::front inplace_vector::back inplace_vector::data Modifiers inplace_vector::clear inplace_vector::erase inplace_vector::swap inplace_vector::insert inplace_vector::insert_range inplace_vector::emplace inplace_vector::emplace_back inplace_vector::try_emplace_back inplace_vector::unchecked_emplace_back inplace_vector::push_back inplace_vector::try_push_back inplace_vector::unchecked_push_back inplace_vector::pop_back inplace_vector::append_range inplace_vector::try_append_range
Non-member functions
erase(std::inplace_vector)erase_if(std::inplace_vector) swap(std::inplace_vector)	operator==operator<=>

 

constexpr reference operator[]( size_type pos );	(1)	(since C++26)
constexpr const_reference operator[]( size_type pos ) const;	(2)	(since C++26)

Returns a reference to the element at specified location pos. No bounds checking is performed.

Parameters

pos

-

position of the element to return

Return value

Reference to the requested element.

Complexity

Constant.

Notes

Unlike std::map::operator[], this operator never inserts a new element into the container. Accessing a nonexistent element through this operator is undefined behavior.

Example

The following code uses operator[] to read from and write to a std::inplace_vector<int, N>:

Run this code

#include <inplace_vector>
#include <iostream>
 
int main()
{
    std::inplace_vector<int, 4> numbers{2, 4, 6, 8};
 
    std::cout << "Second element: " << numbers[1] << '\n';
 
    numbers[0] = 5;
 
    std::cout << "All numbers:";
    for (auto i : numbers)
        std::cout << ' ' << i;
    std::cout << '\n';
}

Output:

Second element: 4
All numbers: 5 4 6 8

See also

at	access specified element with bounds checking (public member function)