std::deque<T,Allocator>:: operator[]

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

Parameters

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

#include <deque>
#include <iostream>
 
int main()
{
    std::deque<int> 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';
}

Second element: 4
All numbers: 5 4 6 8

See also