C++ String Namespace
Omitting Namespace
You might see some C++ programs that runs without the standard namespace library. The using namespace std line can be omitted and replaced with the std keyword, 
followed by the :: operator 
for string (and cout) objects:
Example
  #include <iostream>
#include <string>
int main() {
 
  std::string greeting = "Hello";
  std::cout 
  << greeting;
  return 0;
}
Try it Yourself »
It is up to you if you want to include the standard namespace library or not.
