table of contents
std::array::at(3) | C++ Standard Libary | std::array::at(3) |
NAME¶
std::array::at - std::array::at
Synopsis¶
reference at( size_type pos ); (until C++17)
constexpr reference at( size_type pos ); (since C++17)
const_reference at( size_type pos ) const; (until C++14)
constexpr const_reference at( size_type pos ) const; (since C++14)
Returns a reference to the element at specified location pos, with bounds
checking.
If pos is not within the range of the container, an exception of type
std::out_of_range is thrown.
Parameters¶
pos - position of the element to return
Return value¶
Reference to the requested element.
Exceptions¶
std::out_of_range if !(pos < size()).
Complexity¶
Constant.
Example¶
// Run this code
#include <iostream>
#include <array>
int main()
{
std::array<int,6> data = { 1, 2, 4, 5, 5, 6 };
// Set element 1
data.at(1) = 88;
// Read element 2
std::cout << "Element at index 2 has value " <<
data.at(2) << '\n';
std::cout << "data size = " << data.size() <<
'\n';
try {
// Set element 6
data.at(6) = 666;
} catch (std::out_of_range const& exc) {
std::cout << exc.what() << '\n';
}
// Print final values
std::cout << "data:";
for (int elem : data)
std::cout << " " << elem;
std::cout << '\n';
}
Possible output:¶
Element at index 2 has value 4
data size = 6
array::at: __n (which is 6) >= _Nm (which is 6)
data: 1 88 4 5 5 6
See also¶
operator[] access specified element
(C++11) (public member function)
2022.07.31 | http://cppreference.com |