Explain how to query for null and zero-length string values.
What will be an ideal response?
Query for zero-length string values by entering "" as the criterion.
Query for null values by entering Is Null as the criterion.
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The number of elements in an array can be determined using the array's ____ property.
A. index B. constructor C. input D. length
Which statement is false:
a. A weak_ptr points to the resource managed by a shared_ptr without assuming any responsibility for it. b. The reference count for a shared_ptr doesn’t increase when a weak_ptr references it. That means that the resource of a shared_ptr can be deleted while there are still weak_ptrs pointing to it. When the last shared_ptr is destroyed, the resource is deleted and any remaining weak_ptrs are set to NULL. c. One use for weak_ptr s is to avoid memory leaks caused by circular references. d. None of the above.
An array which has memory space set aside for it at compile time is a:
A. heap array B. static array C. dynamic array D. circular array
Supermarkets use ________ to scan codes printed on product containers.
A. OCR readers B. RFID microchips C. bar code readers D. photoelectric cells