C++ Function Definition Add a Function Prototype before main() function

#include <iostream> 

using namespace std; 

void printName(string first, string last); 

int main() /*from  w  w  w.j a v a  2  s.  c  om*/
{ 
  printName("a", "b"); 
  return 0; 
} 

void printName(string first, string last) 
{ 
  string fullname = first + " " + last; 
  cout << fullname << endl; 
}