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std::span back() method

constexpr reference back() const;

Returns a reference

to the last character in the span.

Undefined Behavior

Calling back() on an empty span is undefined behavior

.

Parameters

(none)

Return value

Reference to the last element.

Complexity

Constant - O(1).

Notes

For a span s, the expression s.back() is equivalent to *std::prev(s.end()) and s[s.size() - 1].

Example

Main.cpp
#include <span>
#include <iostream>

int main() {
for (std::span str{"ABCDEF"}; !str.empty(); str.remove_suffix(1))
std::cout << str.back() << ' ' << str << '\n';
}
Output
F ABCDEF
E ABCDE
D ABCD
C ABC
B AB
A A
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Hover to see the original license.

std::span back() method

constexpr reference back() const;

Returns a reference

to the last character in the span.

Undefined Behavior

Calling back() on an empty span is undefined behavior

.

Parameters

(none)

Return value

Reference to the last element.

Complexity

Constant - O(1).

Notes

For a span s, the expression s.back() is equivalent to *std::prev(s.end()) and s[s.size() - 1].

Example

Main.cpp
#include <span>
#include <iostream>

int main() {
for (std::span str{"ABCDEF"}; !str.empty(); str.remove_suffix(1))
std::cout << str.back() << ' ' << str << '\n';
}
Output
F ABCDEF
E ABCDE
D ABCD
C ABC
B AB
A A
This article originates from this CppReference page. It was likely altered for improvements or editors' preference. Click "Edit this page" to see all changes made to this document.
Hover to see the original license.