Difference between revisions of "cpp/container/vector/front"
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Latest revision as of 11:07, 5 November 2023
| reference front(); |
(1) | (constexpr since C++20) |
| const_reference front() const; |
(2) | (constexpr since C++20) |
Returns a reference to the first element in the container.
Calling front on an empty container causes undefined behavior.
Contents |
[edit] Parameters
(none)
[edit] Return value
Reference to the first element.
[edit] Complexity
Constant.
[edit] Notes
For a container c, the expression c.front() is equivalent to *c.begin().
[edit] Example
The following code uses front to display the first element of a std::vector<char>:
Run this code
#include <cassert> #include <vector> int main() { std::vector<char> letters{'a', 'b', 'c', 'd'}; assert(letters.front() == 'a'); }
[edit] See also
| access the last element (public member function) | |
| (C++11) |
returns a reverse iterator to the end (public member function) |
| (C++11) |
returns an iterator to the beginning (public member function) |
| direct access to the underlying contiguous storage (public member function) |
