std::string_view find() method
- od C++17
// (1) Const version only
constexpr size_type find( basic_string_view v, size_type pos = 0 ) const noexcept;
// (2) Const version only
constexpr size_type find( CharT ch, size_type pos = 0 ) const noexcept;
// (3) Const version only
constexpr size_type find( const CharT* s, size_type pos, size_type count ) const;
// (4) Const version only
constexpr size_type find( const CharT* s, size_type pos = 0 ) const;
Finds the first substring equal to the given character sequence.
- (1) Finds the first occurence of
v
in this view, starting at positionpos
. - (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 forpos
- position at which to start the searchcount
- length of substring to search fors
- pointer to a character string to search forch
- 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.
important
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Exceptions
(none)
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"));
}
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