std::basic_string_view<CharT,Traits>::find

 

哋它亢++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (哋它亢++20)

Language support library

Concepts library (哋它亢++20)

Metaprogramming library (哋它亢++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (哋它亢++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (哋它亢++17)

Regular expressions library (哋它亢++11)

Concurrency support library (哋它亢++11)

Technical specifications

Symbols index

External libraries

 

Strings library

Null-terminated strings

Byte strings

Multibyte strings

Wide strings

Classes

basic_string

basic_string_view (哋它亢++17)

char_traits

 

std::basic_string_view

Member functions basic_string_view::basic_string_view    basic_string_view::operator= Iterators basic_string_view::beginbasic_string_view::cbegin basic_string_view::endbasic_string_view::cend basic_string_view::rbeginbasic_string_view::crbegin basic_string_view::rendbasic_string_view::crend Element access basic_string_view::at basic_string_view::operator[] basic_string_view::front basic_string_view::back basic_string_view::data Capacity basic_string_view::sizebasic_string_view::length basic_string_view::max_size basic_string_view::empty Modifiers basic_string_view::remove_prefix basic_string_view::remove_suffix basic_string_view::swap

Operations basic_string_view::copy basic_string_view::substr basic_string_view::compare basic_string_view::starts_with (哋它亢++20) basic_string_view::ends_with (哋它亢++20) basic_string_view::contains (哋它亢++23) basic_string_view::find basic_string_view::rfind basic_string_view::find_first_of basic_string_view::find_last_of basic_string_view::find_first_not_of basic_string_view::find_last_not_of Constants basic_string_view::npos Non-member functions operator==operator!=operator<operator>operator<=operator>=operator<=> (until 哋它亢++20)(until 哋它亢++20)(until 哋它亢++20)(until 哋它亢++20)(until 哋它亢++20)(哋它亢++20) operator<< operator""sv Helper classes hash<std::string_view>hash<std::wstring_view>hash<std::u8string_view>hash<std::u16string_view>hash<std::u32string_view> (哋它亢++20) Deduction guides(哋它亢++20)

 

constexpr size_type find( basic_string_view v, size_type pos = 0 ) const noexcept;	(1)	(since 哋它亢++17)
constexpr size_type find( CharT ch, size_type pos = 0 ) const noexcept;	(2)	(since 哋它亢++17)
constexpr size_type find( const CharT* s, size_type pos, size_type count ) const;	(3)	(since 哋它亢++17)
constexpr size_type find( const CharT* s, size_type pos = 0 ) const;	(4)	(since 哋它亢++17)

Finds the first substring equal to the given character sequence.

1) Finds the first occurence of v in this view, starting at position pos.

2) Equivalent to find(basic_string_view(std::addressof(ch), 1), pos).

3) Equivalent to find(basic_string_view(s, count), pos).

4) Equivalent to find(basic_string_view(s), pos).

Parameters

v	-	view to search for
pos	-	position at which to start the search
count	-	length of substring to search for
s	-	pointer to a character string to search for
ch	-	character to search for

Return value

Position of the first character of the found substring, or npos if no such substring is found.

Complexity

O(size() * v.size()) at worst.

Example

Run this code

#include <string_view>
 
int main()
{
    using namespace std::literals;
 
    constexpr auto str{" long long int;"sv};
 
    static_assert(
        1 == str.find("long"sv)            && "<- find(v , pos = 0)" &&
        6 == str.find("long"sv, 2)         && "<- find(v , pos = 2)" &&
        0 == str.find(' ')                 && "<- find(ch, pos = 0)" &&
        2 == str.find('o', 1)              && "<- find(ch, pos = 1)" &&
        2 == str.find("on")                && "<- find(s , pos = 0)" &&
        6 == str.find("long double", 5, 4) && "<- find(s , pos = 5, count = 4)"
    );
 
    static_assert(str.npos == str.find("float"));
}

See also

rfind	find the last occurrence of a substring (public member function)
find_first_of	find first occurrence of characters (public member function)
find_last_of	find last occurrence of characters (public member function)
find_first_not_of	find first absence of characters (public member function)
find_last_not_of	find last absence of characters (public member function)
find	finds the first occurrence of the given substring (public member function of std::basic_string<CharT,Traits,Allocator>)