--- title: "array" weight: 1 --- {{< callout >}} Header: `array.h` Since: All versions Similar to: [std::array](https://en.cppreference.com/w/cpp/container/array.html) {{< /callout >}} A fixed capacity array. Adds additional members functions, `assign`, `insert` & `erase`. ```cpp etl::array ``` See also: [array_view]({{< relref "array-view" >}}) [multi_array]({{< relref "multi-array" >}}) ## Template deduction guides **C++17 and above** ```cpp template etl::array(T...) ``` ### Example ```cpp etl::array data{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 }; ``` Defines data as an array of 'int', of length '10', containing the supplied data. ## Make template **C++11 and above** ```cpp template constexpr auto make_array(TValues&&... values) ``` ### Example ```cpp auto data = etl::make_array(0, 1, 2, 3, 4, 5, 6, 7, 8, 9); ``` ## Member types `value_type` `size_type` `difference_type` `reference` `const_reference` `pointer` `const_pointer` `iterator` `const_iterator` `reverse_iterator` `const_reverse_iterator` `etl::array` iterators are random access. ## Static Constants ```cpp SIZE ``` **Description** The size of the array. ## Constructor ```cpp etl::array data = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 }; ``` **Description** Default or copy constructs each element. Can be initialised like a C array. ## Element access ```cpp T& at(size_t i) const T& at(size_t i) const ``` **Description** Returns a reference or const reference to the indexed element. Emits an etl::array_out_of_range if the index is not in range. If asserts or exceptions are not enabled then an out of range index results in undefined behaviour. --- ```cpp T& operator[](size_t i) const T& operator[](size_t i) const ``` **Description** Returns a reference or const reference to the indexed element. An out of range index results in undefined behaviour. --- ```cpp T& front() const T& front() const ``` **Description** Returns a reference or const reference to the first element. --- ```cpp T& back() const T& back() const ``` **Description** Returns a reference or const reference to the last element. ## Iterators ```cpp iterator begin() const_iterator begin() const const_iterator cbegin() const ``` **Description** Returns an iterator to the beginning of the array. --- ```cpp iterator end() const_iterator end() const const_iterator cend() const ``` **Description** Returns an iterator to the end of the array. --- ```cpp iterator rbegin() const_iterator rbegin() const const_iterator crbegin() const ``` **Description** Returns a reverse iterator to the beginning of the array. --- ```cpp iterator rend() const_iterator rend() const const_iterator crend() const ``` **Description** Returns a reverse iterator to the end of the array. ## Capacity ```cpp bool empty() const ``` **Description** Returns true if the size of the array is zero, otherwise false. --- ```cpp size_t size() const ``` **Description** Returns the size of the array. --- ```cpp size_t max_size() const ``` **Description** Returns the maximum possible size of the array. ## Modifiers ```cpp void fill(T value) ``` **Description** Fills the array with value. ## ETL Extensions ```cpp template void assign(TIterator first, const TIterator last) ``` ```cpp template void assign(TIterator first, const TIterator last, parameter_t value) ``` **Description** Assigns a range of values to the array. The second form set uninitialised elements to value. If the range is larger than the array then the extra data is ignored. If the range is smaller than the array then the unused array elements are left unmodified. --- ```cpp iterator insert_at(size_t position, parameter_t value) iterator insert(const_iterator position, parameter_t value) ``` **Description** Inserts a value into the array at the specified position, shifting elements to make room. Elements may be truncated if they are shifted off the end of the array. --- ```cpp template iterator insert_at(size_t position, TIterator first, const TIterator last) ``` **Description** `position` is not checked for validity. --- ```cpp template iterator insert(const_iterator position, TIterator first, const TIterator last) ``` **Description** Inserts a range of values into the array at the specified position, shifting elements to make room. Elements may be truncated if they are shifted off the end of the array. The range may be larger than the capacity of the array. Excess elements will be ignored. --- ```cpp iterator erase_at(size_t position) iterator erase_at(size_t position, parameter_t value) iterator erase(const_iterator position) iterator erase(const_iterator position, parameter_t value) ``` **Description** Erases an element at the specified position, shifting elements into the space. The value parameter variants initialise the unused elements with value, while the others leave them unchanged. position is not checked for valid range. --- ```cpp iterator erase_range(size_t first, size_t last) iterator erase_range(size_t first, size_t last, parameter_t value) iterator erase(const_iterator first, const_iterator last) iterator erase(const_iterator first, const_iterator last, parameter_t value) ``` **Description** Erases a range, shifting elements into the space. The value parameter variants initialise the unused elements with value, while the others leave them unchanged. first/last are not checked for valid range. ## Non-member functions **Lexicographically comparisons** ```cpp operator == ``` **Description** `true` if the contents of the lists are equal, otherwise `false`. --- ```cpp operator != ``` **Description** `true` if the contents of the lists are not equal, otherwise `false`. --- ```cpp operator < ``` **Description** `true` if the contents of the lhs are lexicographically less than the contents of the rhs, otherwise `false`. --- ```cpp operator <= ``` **Description** `true` if the contents of the lhs are lexicographically less than or equal to the contents of the rhs, otherwise `false`. --- ```cpp operator > ``` **Description** `true` if the contents of the lhs are lexicographically greater than the contents of the rhs, otherwise `false`. --- ```cpp operator >= ``` **Description** `true` if the contents of the lhs are lexicographically greater than or equal to the contents of the rhs, otherwise `false`.