Debug Memory Leak in VC

#define _CRTDBG_MAP_ALLOC
#include <stdlib.h>
#include <crtdbg.h>

_CrtMemState old, new, diff;

_CrtMemCheckpoint(&old);
....
_CrtMemCheckpoint(&new);

_CrtMemDifference(&diff, &old, &new);
_CrtMemDumpStatistics(&diff);

_CrtDumpMemoryLeaks();