std::literals::string_view_literals::operator""sv

constexpr std::string_view
    operator ""sv( const char* str, std::size_t len ) noexcept;

constexpr std::u8string_view
    operator ""sv( const char8_t* str, std::size_t len ) noexcept;

constexpr std::u16string_view
    operator ""sv( const char16_t* str, std::size_t len ) noexcept;

constexpr std::u32string_view
    operator ""sv( const char32_t* str, std::size_t len ) noexcept;

constexpr std::wstring_view
    operator ""sv( const wchar_t* str, std::size_t len ) noexcept;

Erzeugt einen String-View aus einem Zeichenliteral.

Parameter

Rückgabewert

Das std::basic_string_view Literal.

Hinweise

Diese Operatoren sind im Namensraum std::literals::string_view_literals deklariert, wobei sowohl literals als auch string_view_literals Inline-Namensräume sind. Der Zugriff auf diese Operatoren kann durch eine der folgenden Möglichkeiten erfolgen:

• using namespace std :: literals ,
• using namespace std :: string_view_literals , oder
• using namespace std :: literals :: string_view_literals .

Beispiel

#include <iostream>
#include <string_view>
#include <typeinfo>
void print_each_character(const std::string_view sw)
{
    for (char c : sw)
        std::cout << (c == '\0' ? '@' : c);
    std::cout << '\n';
}
int main()
{
    using namespace std::literals;
    std::string_view s1 = "abc\0\0def";
    std::string_view s2 = "abc\0\0def"sv;
    std::cout << "s1.size(): " << s1.size() << "; s1: ";
    print_each_character(s1);
    std::cout << "s2.size(): " << s2.size() << "; s2: ";
    print_each_character(s2);
    std::cout << "substr(1, 4): " << "abcdef"sv.substr(1, 4) << '\n';
    auto value_type_info = []<typename T>(T)
    {
        using V = typename T::value_type;
        std::cout << "sizeof " << typeid(V).name() << ": " << sizeof(V) << '\n';
    };
    value_type_info("char A"sv);
    value_type_info(L"wchar_t ∀"sv);
    value_type_info(u8"char8_t ∆"sv);
    value_type_info(u"char16_t ∇"sv);
    value_type_info(U"char32_t ∃"sv);
    value_type_info(LR"(raw ⊞)"sv);
}

s1.size(): 3; s1: abc
s2.size(): 8; s2: abc@@def
substr(1, 4): bcde
sizeof char: 1
sizeof wchar_t: 4
sizeof char8_t: 1
sizeof char16_t: 2
sizeof char32_t: 4
sizeof wchar_t: 4

Siehe auch