Pointer Subtraction

The formula used by pointer substraction is: ( q - p ) == ( addr( q ) - addr( p ) ) / sizeof( T ) with T being the type of both p and q. int array[10]; int* p1 = array + 2; int* p2 = array + 5; ptrdiff_t a = p2 - p1; // 3 ptrdiff_t b = p1 - p2; //...