I just want a space between first_name and last_name when this output's

#include <iostream>
using namespace std;
int main()

{

   char first_name[15];
   char last_name[15];
   cout << "Please enter your first name \n";
   cin >> first_name;
   cout << "Please enter your last name \n";
   cin >> last_name;
   cout << "Hello " << first_name << last_name << endl;

   return 0;

}

Just learning...Thanks!!!! Kevin