1. uninitialized_fill_n(ForwardIter first, Size n, const T& value)

從 first 位置開始，填充 n 個元素值，返回填充結(jié)束的位置

template <class ForwardIter, class Size, class T> ForwardIter uninitialized_fill_n(ForwardIter first, Size n, const T& value) {return mystl::unchecked_uninit_fill_n(first, n, value, std::is_trivially_copy_assignable<typename iterator_traits<ForwardIter>::value_type>{}); }

->

template <class ForwardIter, class Size, class T> ForwardIter unchecked_uninit_fill_n(ForwardIter first, Size n, const T& value, std::true_type) {return mystl::fill_n(first, n, value); }template <class ForwardIter, class Size, class T> ForwardIter unchecked_uninit_fill_n(ForwardIter first, Size n, const T& value, std::false_type) {auto cur = first;try{for (; n > 0; --n, ++cur){mystl::construct(&*cur, value);}}catch (...){for (; first != cur; ++first)mystl::destroy(&*first);}return cur; }

1.1 fill_n

// 從 first 位置開始填充 n 個值 template <class OutputIter, class Size, class T> OutputIter fill_n(OutputIter first, Size n, const T& value) {return unchecked_fill_n(first, n, value); }

->

template <class OutputIter, class Size, class T> OutputIter unchecked_fill_n(OutputIter first, Size n, const T& value) {for (; n > 0; --n, ++first){*first = value;}return first; }// 為 one-byte 類型提供特化版本 template <class Tp, class Size, class Up> typename std::enable_if<std::is_integral<Tp>::value && sizeof(Tp) == 1 &&!std::is_same<Tp, bool>::value &&std::is_integral<Up>::value && sizeof(Up) == 1,Tp*>::type unchecked_fill_n(Tp* first, Size n, Up value) {if (n > 0){std::memset(first, (unsigned char)value, (size_t)(n));}return first + n; }

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