019: at()

at() を定義します。

at() は operator[]() とほぼ同じ形ですが、引数が範囲外の場合に std::out_of_range を投げる点が異なります。

template <typename T>
class myvector
{
...

    /**
     * @brief      Returns a reference to the element at specified location pos,
     *             with bounds checking. If pos is not within the range of the container,
     *             an exception of type std::out_of_range is thrown.
     * @param[in]  pos: Position of the element to return.
     * @return     Reference to the requested element.
     * @throw      std::out_of_range: If pos is not within the range of the container.
     */
    reference at(size_type pos)
    {
        if (pos >= size_) {
            throw std::out_of_range("myvector::at()");
        }
        return heap_[pos];
    }

    /**
     * @brief      Returns a reference to the element at specified location pos,
     *             with bounds checking. If pos is not within the range of the container,
     *             an exception of type std::out_of_range is thrown.
     * @param[in]  pos: Position of the element to return.
     * @return     Const reference to the requested element.
     * @throw      std::out_of_range: If pos is not within the range of the container.
     */
    const_reference at(size_type pos) const
    {
        if (pos >= size_) {
            throw std::out_of_range("myvector::at() const");
        }
        return heap_[pos];
    }

    ...
};

at() は２種類ありますが、違いは const関数であるか、非const関数であるか、のみです。


全ソースコード： https://github.com/suomesta/myvector/tree/master/019