# string ## 字符串字面量 ~~~ const char* a = "string a"; const char* b = u8"string b"; // UTF-8 const char16_t* c = u"string c"; // UTF-16 const char32_t* d = U"string d"; // UTF-32 const char* e = R"(string e1 "\\ stirng e2)"; // raw string std::cout << a << std::endl; std::cout << b << std::endl; std::cout << c << std::endl; std::cout << d << std::endl; std::cout << e << std::endl; R原始字符 auto xml = R"(<root> <item value="1"> <item value="2"> </root>)"; ~~~ ## string常用方法 ``` string str1 = "Hello World" string str2 = "Hello World"s string str2 = "hellow"sv string_veiw类型 ``` ``` ``` ## 高级数值转换 ``` 定义于头文件 <string> std::string to_string( int value ); std::string to_string( long value ); std::string to_string( long long value ); std::string to_string( unsigned value ); std::string to_string( unsigned long value ); std::string to_string( unsigned long long value ); std::string to_string( float value ); std::string to_string( double value ); std::string to_string( long double value ); stoi stol stoll 转换字符串为有符号整数 (函数) stoul stoull 转换字符串为无符号整数 (函数) stof stod stold 转换字符串为浮点值 ```