(C++17) | ||||
| Sequence | ||||
(C++11) | ||||
(C++26) | ||||
(C++26) | ||||
(C++11) | ||||
| Associative | ||||
| Unordered associative | ||||
(C++11) | ||||
(C++11) | ||||
(C++11) | ||||
(C++11) | ||||
| Adaptors | ||||
(C++23) | ||||
(C++23) | ||||
(C++23) | ||||
(C++23) | ||||
| Views | ||||
(C++20) | ||||
(C++23) | ||||
| Tables | ||||
| Iterator invalidation | ||||
| Member function table | ||||
| Non-member function table |
| Member types | ||||||
| Member functions | ||||||
| Non-member functions | ||||||
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| Helper classes | ||||||
| Deduction guides(C++17) | ||||||
reference front(); | (1) | (since C++11) (constexpr since C++17) |
const_reference front()const; | (2) | (since C++11) (constexpr since C++14) |
Returns a reference to the first element in the container.
Ifempty() istrue, the behavior is undefined. | (until C++26) |
Ifempty() istrue:
| (since C++26) |
Contents |
Reference to the first element.
Constant.
For a containerc, the expressionc.front() is equivalent to*c.begin().
The following code usesfront to display the first element of astd::array<char,4>:
#include <cassert>#include <array> int main(){std::array<char,4> letters{'a','b','c','d'};assert(letters.front()=='a');}
| access the last element (public member function)[edit] | |
| returns a reverse iterator to the end (public member function)[edit] | |
| returns an iterator to the beginning (public member function)[edit] | |
| direct access to the underlying contiguous storage (public member function)[edit] |
