title: error: 'string_view' is not a member of 'std'
body: <p>i am new to c++. i compiled my code in visual-studio-code in windows10, with 2 variables of type string and string_view. string variable is fine, but string_view is giving errors.I also enable c++17 extension in configuration.json and edit configuration/ui file in vscode.</p>
  
  <p>Here is my code:=</p>
  
  <pre><code>#include&lt;iostream&gt;
  #include&lt;string_view&gt;
  using namespace std;
  int main(){
        string str="hello";
        cout&lt;&lt;str&lt;&lt;endl;
        std::string_view sv=" world";
        auto result=str+sv.data();
  
        return 0;
  }
  </code></pre>
  
  <p>errors are:=</p>
  
  <pre><code>main.cpp: In function 'int main()':
  main.cpp:7:12: error: 'string_view' is not a member of 'std'
         std::string_view sv=" world";
              ^~~~~~~~~~~
  main.cpp:7:12: note: 'std::string_view' is only available from C++17 onwards
  main.cpp:8:23: error: 'sv' was not declared in this scope
         auto result=str+sv.data();
                         ^~
  </code></pre>