std::inplace_vector<T,N>::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, unless the implementation is hardened.

If pos < size() is false:

If the implementation is hardened, a contract violation occurs.
If the implementation is not hardened, the behavior is undefined.

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, unless the implementation is hardened.

Example

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

#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: