table of contents
std::span::back(3) | C++ Standard Libary | std::span::back(3) |
NAME¶
std::span::back - std::span::back
Synopsis¶
constexpr reference back() const;
Returns a reference to the last element in the span.
Calling back on an empty span results in undefined behavior.
Parameters¶
(none)
Return value¶
A reference to the back element.
Complexity¶
Constant
Notes¶
For a span c, the expression c.back() is equivalent to *(c.end()-1).
Example¶
// Run this code
#include <span>
#include <iostream>
void print_forward(std::span<const int> const span) {
for (auto n { span.size() }; n != 0; --n ) {
std::cout << span.last(n).front() << ' ';
}
std::cout << '\n';
}
void print_backward(std::span<const int> const span) {
for (auto n { span.size() }; n != 0; --n) {
std::cout << span.first(n).back() << ' ';
}
std::cout << '\n';
}
int main()
{
constexpr int numbers[] { 0, 1, 2, 3, 4 };
print_forward(numbers);
print_backward(numbers);
}
Output:¶
0 1 2 3 4
4 3 2 1 0
See also¶
front access the first element
(C++20) (public member function)
2022.07.31 | http://cppreference.com |