std::copy, std::copy_if

 

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功能 Original: Functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
修改序列操作 Original: Non-modifying sequence operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
all_of any_of none_of （C++11） （C++11） （C++11） for_each count count_if mismatch equal	find find_if find_if_not （C++11） find_end find_first_of adjacent_find search search_n
修改序列操作 Original: Modifying sequence operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
copy copy_if （C++11） copy_n （C++11） copy_backward move （C++11） move_backward （C++11） fill fill_n transform generate generate_n remove remove_if remove_copy remove_copy_if	replace replace_if replace_copy replace_copy_if swap swap_ranges iter_swap reverse reverse_copy rotate rotate_copy random_shuffle shuffle   （C++11） unique unique_copy
分區操作 Original: Partitioning operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_partitioned （C++11） partition partition_copy （C++11）	stable_partition partition_point （C++11）
排序操作（排序的區間） Original: Sorting operations (on sorted ranges) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_sorted （C++11） is_sorted_until （C++11） sort	partial_sort partial_sort_copy stable_sort nth_element
二進制搜索操作（排序的區間） Original: Binary search operations (on sorted ranges) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
lower_bound upper_bound	binary_search equal_range
設置操作（排序的區間） Original: Set operations (on sorted ranges) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
merge inplace_merge includes	set_difference set_intersection set_symmetric_difference set_union
堆的操作 Original: Heap operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_heap is_heap_until （C++11） make_heap	push_heap pop_heap sort_heap
最小/最大操作 Original: Minimum/maximum operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
max max_element min min_element minmax （C++11） minmax_element （C++11）	lexicographical_compare is_permutation （C++11） next_permutation prev_permutation
數字操作 Original: Numeric operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
iota （C++11） accumulate inner_product	adjacent_difference partial_sum
C庫 Original: C library The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
qsort	bsearch

 

Defined in header <algorithm>
template< class InputIt, class OutputIt > OutputIt copy( InputIt first, InputIt last, OutputIt d_first );	(1)
template< class InputIt, class OutputIt, class UnaryPredicate > OutputIt copy_if( InputIt first, InputIt last,                   OutputIt d_first,                   UnaryPredicate pred );	(2)	（C++11 起）

複製中的元素定義的範圍內，由[first, last)到另一個範圍開始於d_first。第二個功能只有謂詞的元素複製pred回報true.

Original:

Copies the elements in the range, defined by [first, last), to another range beginning at d_first. The second function only copies the elements for which the predicate pred returns true.

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參數

first, last	-	元素的範圍內，要複製的複本 Original: the range of elements to copy The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
d_first	-	的目標範圍的開頭。如果d_first內[first, last)，std::copy_backward必須使用代替std::copy. Original: the beginning of the destination range. If d_first is within [first, last), std::copy_backward must be used instead of std::copy. The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
pred	-	unary predicate which returns ​true 所需的元素 Original: for the required elements The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. . The signature of the predicate function should be equivalent to the following: bool pred(const Type &a); The signature does not need to have const &, but the function must not modify the objects passed to it. The type Type must be such that an object of type InputIt can be dereferenced and then implicitly converted to Type. ​
Type requirements
- InputIt must meet the requirements of InputIterator.
- OutputIt must meet the requirements of OutputIterator.

返回值

輸出迭代器在目標範圍內的元素，複製過去的最後一個元素.

Original:

Output iterator to the element in the destination range, one past the last element copied.

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複雜性

1)

究竟last - first任務

Original:

Exactly last - first assignments

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2)

究竟last - first的謂詞中的應用

Original:

Exactly last - first applications of the predicate

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注釋

在實踐中，實現std::copy避免多次分配和使用大容量複製功能，如std::memcpy如果該值類型是TriviallyCopyable

Original:

In practice, implementations of std::copy avoid multiple assignments and use bulk copy functions such as std::memcpy if the value type is TriviallyCopyable

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可能的實現

First version
template<class InputIt, class OutputIt> OutputIt copy(InputIt first, InputIt last, OutputIt d_first) { while (first != last) { *d_first++ = *first++; } return d_first; }
Second version
template<class InputIt, class OutputIt, class UnaryPredicate> OutputIt copy_if(InputIt first, InputIt last, OutputIt d_first, UnaryPredicate pred) { while (first != last) { if(pred(*first)) *d_first++ = *first; first++; } return d_first; }

為例

下面的代碼複製到一個向量和顯示的內容都複製得到的載體

Original:

The following code uses copy to both copy the contents of one vector to another and to display the resulting vector:

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#include <algorithm>
#include <iostream>
#include <vector>
#include <iterator>
 
int main()
{
    std::vector<int> from_vector;
    for (int i = 0; i < 10; i++) {
        from_vector.push_back(i);
    }
 
    std::vector<int> to_vector(10);
 
    std::copy(from_vector.begin(), from_vector.end(), to_vector.begin());
 
    std::cout << "to_vector contains: ";
    std::copy(to_vector.begin(), to_vector.end(), 
              std::ostream_iterator<int>(std::cout, " "));
    std::cout << std::endl;
}

Output:

to_vector contains: 0 1 2 3 4 5 6 7 8 9

另請參閱

copy_backward	份向後為了在一個範圍內的元素 Original: copies a range of elements in backwards order The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函數模板）
remove_copy remove_copy_if	複製一個範圍內的元素省略了那些滿足特定的條件 Original: copies a range of elements omitting those that satisfy specific criteria The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函數模板）