C++ Certified Professional Programmer Free Sample Questions

The key requirement is to preserve the original insertion order for entries with identical timestamps. The std::stable_sort algorithm is specifically designed for this purpose. It guarantees that the relative order of equivalent elements remains unchanged after sorting. std::sort does not provide this guarantee and may reorder elements with equal keys, which would violate the forensic analysis requirement. The other options are incorrect because std::partition only groups elements based on a predicate without fully sorting them, and std::sort on its own is insufficient.

std::deque provides constant-time insertion and removal at both the front and the back (push_front/pop_front/push_back/pop_back) and constant-time random access via operator[]/at(), meeting every requirement. std::vector has O(1) random access and amortized O(1) back operations, but inserting or erasing at the front shifts every element (O(n)). std::list and std::forward_list offer no index access, and std::stack exposes only one end and no random access.

std::remove_if (and std::remove) cannot alter the size of the container because it only has access to iterators, not the container object itself. It works by moving all elements that do not match the removal criteria to the front of the range and returns an iterator pointing one past the last element that was kept. The elements from this new logical end to the container's actual end are left in a valid but unspecified state. The correct way to physically remove the elements is to call the container's erase method with the iterator range returned by remove_if, a pattern known as the 'erase-remove idiom'.

std::map is an ordered associative container, typically implemented as a red-black tree. To maintain order and determine the correct position for each key, it needs a way to compare two keys. By default, it uses std::less , which in turn calls operator< on the key objects. Therefore, the UserSession struct must provide a public operator< that establishes a strict weak ordering among its instances. Alternatively, a custom comparator function object could be provided as a template argument to the map, but the most common solution is to overload operator<.

This approach is the most efficient because it leverages the fact that the input vectors are already sorted. std::merge, std::set_intersection, and std::set_difference are all linear time O(N+M) algorithms when operating on sorted ranges. std::merge efficiently creates the consolidated list. std::set_intersection produces the common trades, and std::set_difference produces the trades in the first range but not the second. Any approach involving re-sorting (like concatenation followed by std::sort) would be less efficient, with a complexity of O((N+M)log(N+M)).

During C++ overload resolution, the compiler follows a set of rules to select the best function to call. A non-template function that is a perfect match for the argument types is preferred over a template instantiation. In this case, the string literal "hello" has the type const char[6], which decays to const char*. The process(const char*) function is an exact match for this type. The template function process could also be instantiated with T as const char*, but the non-template overload is a better match and will be chosen without hesitation.

The std::find_end algorithm is specifically designed for this purpose. It searches for the last occurrence of a sub-sequence within a larger sequence. It takes iterators for the range to be searched and iterators for the pattern to search for. std::search finds the first occurrence. Using reverse iterators with std::search is tricky because it finds the first occurrence in the reversed sequence, which corresponds to the last occurrence but returns a reverse iterator that needs to be converted back correctly.

Manipulators like std::fixed, std::scientific, std::boolalpha, and std::setprecision modify the internal state of the stream object. This state is persistent and affects all subsequent I/O operations on that stream until the state is explicitly changed by another manipulator. In contrast, manipulators like std::setw only affect the very next output operation.

The code first initializes the vector data to {1, 2, 3, 4, 5} using std::iota. The std::transform algorithm is then used for an in-place modification (source and destination iterators are the same). The lambda function captures the multiplier variable (value 3) by value. It iterates through each element of data. If an element (val) is odd (val % 2 != 0), it returns val * multiplier; otherwise, it returns the original val.

• 1 is odd: 1 * 3 = 3
• 2 is even: 2
• 3 is odd: 3 * 3 = 9
• 4 is even: 4
• 5 is odd: 5 * 3 = 15
  Therefore, the final state of the vector is {3, 2, 9, 4, 15}.

The std::lower_bound algorithm returns an iterator pointing to the first element in the range [first, last) which does not compare less than val. In a sorted range, this is the correct insertion point to maintain order. In the vector {10, 20, 30, 50, 60}, the algorithm is searching for 40. The first element that is not less than 40 is 50. Therefore, the iterator it will point to the element 50, and dereferencing it will print 50.