What happens if an exception occurs in a destructor in C++?
- The program will retry the destructor
- A default destructor is called
- The program terminates
- The exception is ignored
If an exception is thrown from a destructor, and it's not caught within the destructor, the C++ runtime system will terminate the program. Destructors are often invoked during stack unwinding when an exception is thrown, so allowing exceptions to propagate out can lead to unpredictable behavior.
The bitwise NOT operator (~) performs a _______ operation on each bit of a number.
- negation
- AND
- OR
- XOR
The bitwise NOT operator (~) inverts each bit of a number. If the bit is 0, it becomes 1, and if it's 1, it becomes 0. This is essentially a negation operation on individual bits.
The return type of a function that does not return any value is specified as _______.
- char
- int
- double
- void
The "void" return type specifies that a function doesn't return a value. It's used when the primary purpose of the function is to perform an action, not produce data.
What happens if you try to delete memory using the delete operator more than once?
- It gets deleted twice
- No effect
- Program crashes
- Memory gets duplicated
Deleting a memory location more than once leads to undefined behavior, most commonly resulting in program crashes. Always ensure memory is deleted once and pointers are set to nullptr afterwards.
In which year was the C++98 standard officially published?
- 1990
- 1995
- 1998
- 2002
The C++98 standard was officially published in 1998. It was the first standardized version of the C++ language, providing a foundation for many modern C++ features and establishing a baseline for future improvements.
How is a friend class defined in C++?
- By inheriting the original class.
- By using the friendship keyword.
- By prefixing the class with the friend keyword.
- By including the class's header file in the original class.
A friend class in C++ is a class that is given permission to access the private and protected members of another class. To declare a class as a friend of another class, the friend keyword is used before the class declaration in the original class.
To read an entire string from a file, instead of a single character, use the _______ function.
- getline
- read
- fetch
- getString
The getline function is used in C++ to read an entire line from an input stream, such as a file. This is particularly useful when dealing with strings that have spaces or when reading full sentences.
A friend function is defined outside the class but has the ability to access the _______ members of the class.
- static
- private
- public
- mutable
A friend function, although not a member of a class, can access its private and protected members. This provides an external function the capability to interact closely with the internals of the class.
Consider a scenario where you have a large dataset and you need to frequently erase and insert elements in the middle of the data. Which STL container should be avoided in order to prevent frequent reallocations and data movements?
- vector
- list
- deque
- set
The STL vector maintains its elements in a contiguous block of memory. Inserting or erasing elements in the middle requires shifting elements, which can be expensive, especially for large datasets. This might cause frequent reallocations and data movements, impacting performance.
Which type of loop is best suited when the number of iterations is known ahead of time?
- do-while loop
- while loop
- for loop
- recursive function
A for loop is best suited when the number of iterations is known ahead of time, as it allows for an initial statement (typically for initialization), a condition check, and an increment/decrement operation in a compact syntax.