C++字面量前后缀

# 自动推导
using namespace std::string_literals;
auto a = "1234"s;

# 自动推导
using namespace std::string_view_literals;
auto a = "1234"sv;

# 多行文本
R"(acgist
acgist)"

# u8、u、U、L
char8_t、char16_t、char32_t、wchar_t