TITLE: Templates reuse source, not executables (another example)


[ This example adapted from "C++ Gotchas", tutorial notes by
  Tom Cargill, p. 69. ]


template <class T>
class Queue 
{
  public:
    Queue ();

    void enqueue (const T&);
    T    dequeue ();
    int  empty   () const;
};


int main ()
{
    Queue<const char*> qt;
    Queue<char*> qc;

    const char* table [] =
    {
	"table",
	"of",
	"strings",
	0
    };

    for (int i = 0; table [i]; i++)
    {
	qt.enqueue (table [i]);

	int len   = strlen (table [i]);
	char* cap = new char [len+1];

	strcpy (cap, table [i]);
	cap [0] = toupper (cap [0]);
	qc.enqueue (cap);
    }

    return 0;
}


The executable (probably) has two copies of each member function 
of Queue, even though each copy has identical code. One is instantiated
for the type "const char*" and another for the type "char*".