Thread: Assignment position dramatically affecting performance

Say I have the code below:

Code:

#include <dbi.h>

using std::cout;

int main()
{
	clock_t t_start = clock();
	clock_t t_fin;


	DBI *dbh = new DBI;        // position 1
	cout<< "Content-type: text/html\n\n";

	for( long i=0; i<1000000000; i++ )
		;
    cout<< "Counted to a billion!<br />";

	//DBI *dbh = new DBI;        // position 2

	char *env_qs = getenv("QUERY_STRING");
	if( *env_qs == NULL )
		cout<< "exe failed it's purpose<br />";
	else
		cout<< "You said <span style=\"font-family:sans-serif;\">\""
	<< env_qs << "\"</span> to me<br />";

	t_fin = clock();
	cout<< "code took about " << (double)(t_fin - t_start) / CLOCKS_PER_SEC << " secs";

	delete dbh;
	return 0;
}

Note that DBI *dbh isn't used. That should be irrelevant, since its constructor doesn't care.

The app usually takes ~2.5-2.8 secs to complete when the commented line is in position 2, but ~3.75-4 secs in position 1. I am utterly baffled that there is a difference, let alone the (relatively) huge discrepancy that comes up here. I've made sure the difference is consistent, and not just me but I haven't a clue as to explaining it. Any suggestions?