struct abc{
     String b;
   public:
       abc( String& xx){
         b=xx;    
       }
       void fecha(){
          b="retornado";   // this not return: reference constructor is address 
       }
       ~abc(){};
};

struct de{
     String* b;
   public:
       de( String* xx){
         b=xx;    
       }
       void fecha(){
          *b="retornado";  // this return: reference constructor is pointer
       }
       ~de(){};
};


void rotina1( String &s )
{
   s="123";	
}
void rotina2( String *s )
{
   *s="yyy";	
}

CONSOLE_APP_MAIN   
{

   String st="abc";
   
   rotina1(st);
   
   Cout() << "after rotina1:  " << st << EOL;  
   
   String* a = &st;
   
   rotina2(a);
   
   Cout() << "after rotina2: "<< *a << EOL;  
   
   abc c(*a);
   c.fecha();
   c.~abc();
   
   Cout() << "after struct abc: "<< *a << EOL;  

   de d(a);
   d.fecha();
   d.~de();
   
   Cout() << "after struct de: "<< *a << EOL;  
	
}

struct abc{
     String b;
   public:
       abc( String& xx){
         b=xx;  // <-- the xx variable will be copied to b;    
       }
       void fecha(){
          b="retornado";   // this not return: reference constructor is address (No, because you are not working on a reference. You are working on a local variable called "b", which will be destroyed with the struct, by the way.) 
       }
       ~abc(){}; // << - Will destroy b.
};

struct abc{
     String& b; // <-- Now b is a reference.
   public:
       abc( String& xx)
           : b(xx) // >  B will refer to xx;
       {
       }
       void fecha(){
          b="retornado";  // Will now set the referred object (xx).
       }
       ~abc(){}; // << - Will not destroy what b refers to (xx).
};