Standard Template Library

16.In C++ STL, what is the default order of elements in a priority_queue?
  • A. Ascending
  • B. Descending
  • C. Random
  • D. It depends on the comparator used.

Descending

Descending

17.Which of the following containers would you use if you need an ordered collection of unique elements, but without duplicates?
  • A. Vector
  • B. Set
  • C. Multimap
  • D. Unordered_map

Set

Set

18.What does the emplace() function do in C++ STL containers?
  • A. It adds an element at the end.
  • B. It creates and inserts an element in place (more efficient).
  • C. It returns the element after insertion.
  • D. It searches for an element and removes it.

It creates and inserts an element in place (more efficient).

It creates and inserts an element in place (more efficient).

19.In C++ STL, what happens if you try to insert a duplicate key into a map container?
  • A. The duplicate key is ignored.
  • B. A runtime error occurs.
  • C. The value of the key is updated.
  • D. The insertion fails silently.

The duplicate key is ignored.

The duplicate key is ignored.