std::basic_string_view<CharT,Traits>::find
constexpr size_type find( basic_string_view v, size_type pos = 0 ) const noexcept; |
(1) | (since C++17) |
constexpr size_type find( CharT ch, size_type pos = 0 ) const noexcept; |
(2) | (since C++17) |
constexpr size_type find( const CharT* s, size_type pos, size_type count ) const; |
(3) | (since C++17) |
constexpr size_type find( const CharT* s, size_type pos = 0 ) const; |
(4) | (since C++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
#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
|
(C++17)
|
find the last occurrence of a substring (public member function) |
|
(C++17)
|
find first occurrence of characters (public member function) |
|
(C++17)
|
find last occurrence of characters (public member function) |
|
(C++17)
|
find first absence of characters (public member function) |
|
(C++17)
|
find last absence of characters (public member function) |
| find characters in the string (public member function of std::basic_string<CharT,Traits,Allocator>) |
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