* @brief AndQuery::eval * @return the intersection of its operands' result sets */

for ex17.4 return a vector with an entry for each store that sold the given book.

fake function that makes the program compile

get the underlying pointer

non-member

add and remove elements

add and remove elements

* @brief do a query opertion and return QueryResult object. */

* @brief do a query opertion and return QueryResult object. */

number of elements in the Blob

number of elements in the Blob

for ex11.4

for ex11.4

Use count