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std::array::operator[](3) | C++ Standard Libary | std::array::operator[](3) |
NAME¶
std::array::operator[] - std::array::operator[]
Synopsis¶
reference operator[]( size_type pos ); (until C++17)
constexpr reference operator[]( size_type pos ); (since C++17)
const_reference operator[]( size_type pos ) const; (until C++14)
constexpr const_reference operator[]( size_type pos ) const; (since
C++14)
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::array<int>:
// Run this code
#include <array>
#include <iostream>
int main()
{
std::array<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
(C++11) (public member function)
2022.07.31 | http://cppreference.com |