If you have to write a function that accepts a string, what type of parameter will you use? You have a couple of choices:<\/p>\n
C++17 makes it easy by introducing a new type called std::string_view<\/strong>. From now on, if you are writing a function that accepts a string, use an std::string_view<\/strong> as parameter type. No need to use an std::string_view<\/strong> reference. A string_view<\/strong> is very cheap to copy, so it’s perfectly fine to pass by value. Basically, a string_view<\/strong> just contains a pointer to a string, and its length. A string_view<\/strong> parameter accepts any kind of string, such as a C++ std::string<\/strong>, a C-style const char*<\/strong> string, and a string literal, all without any copying involved!<\/p>\n std::string_view<\/strong> is defined in the <string_view><\/strong> header. It has a similar interface as the well-known std::string<\/strong> class. However, since a string_view<\/strong> is a read-only view of a string, only the const<\/strong> operations of std::string<\/strong> are supported on a string_view<\/strong>. Additionally, a big advantage of a string_view<\/strong> is that it will never copy a string.<\/p>\n Here is a very brief example of its usage:<\/p>\n The output of this piece of code is as follows:<\/p>\n#include <iostream>\r\n#include <string_view>\r\n\r\nusing namespace std;\r\n\r\nvoid ProcessString(string_view myString)\r\n{\r\n cout << myString; if (myString.size() >= 4)\r\n {\r\n cout << " (Substring: " << myString.substr(2, 2) << ")";\r\n }\r\n cout << endl;\r\n}\r\n\r\nint main()\r\n{\r\n string myString1 = "Hello";\r\n const char* myString2 = "C++";\r\n ProcessString(myString1); \/\/ C++ string\r\n ProcessString(myString2); \/\/ C-style string\r\n ProcessString("World!"); \/\/ String literal\r\n}<\/pre>\nHello (Substring: ll)\r\nC++\r\nWorld! (Substring: rl)<\/pre>\n