To define an abstract class in C++, at least one member function must be declared as _______.
- inline
- pure virtual
- private
- constant
In C++, an abstract class is defined by having at least one pure virtual function. This means the function is declared but not defined within the class, ensuring that derived classes must implement it.
To remove all instances of a particular value from a C++ STL vector, you should use the _______ algorithm.
- find
- sort
- erase
- remove
While erase can remove elements from a vector, to efficiently remove all instances of a value, you'd first use remove to move those elements to the end and then use erase. This is known as the "erase-remove" idiom in C++.
The keyword _______ is used to access the base class’s members in the derived class.
- super
- this
- parent
- base
In C++, the "base" keyword is not actually used. The correct way to access base class members is through the use of the base class name or the scope resolution operator. However, "base" is a term from C#.
The concept of encapsulation involves bundling the data () and the methods () that operate on the data into a single unit.
- objects, functions
- variables, operators
- members, methods
- attributes, functions
Encapsulation is a key concept in object-oriented programming where the data (members) and the functions (methods) that operate on this data are bundled together as a single unit known as a class.
Which of the following is a correct statement about friend functions in C++?
- They are member functions of a class
- They can be inherited by derived classes
- They always improve performance of the program
- They do not have access to the 'this' pointer of the class
In C++, the 'this' pointer is an implicit pointer to the object on which a member function is called. Since friend functions are not member functions of a class, they do not have access to this pointer. They operate as external functions with special access permissions.
In a C++ application, you have a stream of data being logged...
- Write to a temporary file first
- Use std::ofstream::flush after every write
- Use file locking mechanisms
- Implement journaling or write-ahead logging
Implementing journaling or write-ahead logging means changes are first logged to a separate, sequential log. In case of failures, this log can be used to bring the file back to a consistent state. This provides a safeguard against data corruption or loss during unforeseen events.
You are designing a complex numerical algorithm with multiple cooperating classes that need to share internal data for efficiency. How might the friend keyword be used effectively in this context?
- Use the friend keyword for all member functions.
- Limit the use of friend to only those classes/functions that strictly require access.
- Use the friend keyword with external utility functions only.
- Declare all classes as friends of each other.
The friend keyword should be used judiciously. By limiting its use only to those classes or functions that genuinely need access, you maintain a degree of encapsulation and make the design intent clear, ensuring that only necessary components have deeper access.
A function without any parameters is declared with the keyword _______ in the parentheses.
- auto
- void
- int
- default
When declaring a function with no parameters in C++, the keyword "void" is used within the parentheses to explicitly state that no arguments are expected.
Considering cache efficiency, which STL container will provide the fastest element access and iteration in most cases?
- std::list
- std::deque
- std::vector
- std::set
std::vector is a dynamic array implementation. Due to its contiguous memory storage, it provides the best cache locality among the listed STL containers. This leads to faster element access and iteration, especially when compared to non-contiguous storage containers like std::list or node-based containers like std::set.
What feature of C++ templates allows you to provide a specific implementation for particular data types when certain types require a different implementation for optimal performance in a class template?
- Template specialization
- Template instantiation
- Function overloading
- Class inheritance
Template specialization is a feature in C++ that allows developers to define a different implementation of a template for a specific data type. This is especially useful when certain data types require unique handling or optimization compared to the general template definition.