std::string_view find_first_not_of() method

since C++17

// (1) Const version only
constexpr size_type find_first_not_of( const basic_string& str, size_type pos = 0 ) const noexcept;

// (2) Const version only
constexpr size_type find_first_not_of( const CharT* s, size_type pos, size_type count ) const;

// (3) Const version only
constexpr size_type find_first_not_of( const CharT* s, size_type pos = 0 ) const;

// (4) Const version only
constexpr size_type find_first_not_of( CharT ch, size_type pos = 0 ) const noexcept;

Finds the first character not equal to any of the characters in the given character sequence.

• (1) Finds the first character not equal to any of the characters of v in this view, starting at position pos.
• (2) Equivalent to find_first_not_of(basic_string_view(std::addressof(c), 1), pos).
• (3) Equivalent to find_first_not_of(basic_string_view(s, count), pos).
• (4) Equivalent to find_first_not_of(basic_string_view(s), pos).

Parameters

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

Return value

Position of the first character not equal to any of the characters in the given string, 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>
using namespace std::literals;
 
int main()
{
    static_assert(2 == "BCDEF"sv.find_first_not_of("ABC"));
                    //    ^
    static_assert(4 == "BCDEF"sv.find_first_not_of("ABC", 4));
                    //      ^
    static_assert(1 == "BCDEF"sv.find_first_not_of('B'));
                    //   ^
    static_assert(3 == "BCDEF"sv.find_first_not_of('D', 2));
                    //     ^
}