std::search_C++中文网

ForwardIt1 search( ForwardIt1 first, ForwardIt1 last,

ForwardIt2 s_first, ForwardIt2 s_last );

(3)

template< class ForwardIt1, class ForwardIt2, class BinaryPredicate >

ForwardIt1 search( ForwardIt1 first, ForwardIt1 last,

ForwardIt2 s_first, ForwardIt2 s_last, BinaryPredicate p );

(C++20 前)

template< class ForwardIt1, class ForwardIt2, class BinaryPredicate >

constexpr ForwardIt1 search( ForwardIt1 first, ForwardIt1 last,

ForwardIt2 s_first, ForwardIt2 s_last, BinaryPredicate p );

(C++20 起)

1-4) 指向范围中 [first, last - (s_last - s_first)) ，首个子序列 [s_first, s_last) 起始的迭代器。若找不到这种子序列，则返回 last 。
若 [s_first, s_last) 为空，则返回 first 。(C++11 起)

版本一

template<class ForwardIt1, class ForwardIt2>
ForwardIt1 search(ForwardIt1 first, ForwardIt1 last,
                        ForwardIt2 s_first, ForwardIt2 s_last)
{
    for (; ; ++first) {
        ForwardIt1 it = first;
        for (ForwardIt2 s_it = s_first; ; ++it, ++s_it) {
            if (s_it == s_last) {
                return first;
            }
            if (it == last) {
                return last;
            }
            if (!(*it == *s_it)) {
                break;
            }
        }
    }
}

版本二

template<class ForwardIt1, class ForwardIt2, class BinaryPredicate>
ForwardIt1 search(ForwardIt1 first, ForwardIt1 last,
                        ForwardIt2 s_first, ForwardIt2 s_last, 
                        BinaryPredicate p)
{
    for (; ; ++first) {
        ForwardIt1 it = first;
        for (ForwardIt2 s_it = s_first; ; ++it, ++s_it) {
            if (s_it == s_last) {
                return first;
            }
            if (it == last) {
                return last;
            }
            if (!p(*it, *s_it)) {
                break;
            }
        }
    }
}