warning: extended initializer lists only available with -std=c++11 or -std=gnu++11 [enabled by default]

I don't know why I am getting below error

" warning: extended initializer lists only available with -std=c++11 or -std=gnu++11 [enabled by default]"

I have .h and .cpp file

in .h file, I have declare variable name

 class file
 {
   private:
     string* arr;
   public:
     void list();
 }

in .cpp file

void file::list()
{
  arr = new string[2]{"1", "2"}; 
}