A function that does not return a value has a return type of _______.
- void
- int
- char
- bool
In C++, if a function is not returning any value, its return type is void. It indicates that the function does not return a value to the calling function.
In C++, the return statement cannot be used inside a _______.
- constructor
- destructor
- class
- loop
In C++, constructors are used for initializing objects. They don't return values, not even void. Therefore, the return statement is not allowed inside a constructor.
Imagine a function that performs file I/O and may throw an exception. What might be a concern if this function is used inside a constructor, and how might it be addressed?
- The object may not be fully constructed.
- Memory leaks could occur.
- An invalid object can be accessed elsewhere in the code.
- File operations might be slow.
If an exception is thrown during the construction of an object, that object's destructor will not be called since the object was never fully constructed. This can lead to resource leaks or other inconsistencies. It's crucial to ensure that if a constructor might throw an exception, all resources acquired up to that point are properly released to prevent such issues. Proper exception handling and resource management techniques, like RAII, are essential.
Which loop structure is guaranteed to execute at least once even if the condition is false?
- for loop
- while loop
- do-while loop
- switch-case
The do-while loop is designed to execute its block of code at least once before checking the condition. This ensures that the loop body runs even if the condition is false from the start.
How might you address concerns about function templates impacting compilation times and binary size in a high-performance scientific computing application?
- Use inline functions
- Reduce template instantiation
- Avoid using templates
- Optimize template definitions
Function templates can increase both compilation times and the size of the binary due to multiple instantiations for different data types. One way to address these concerns is by reducing unnecessary template instantiations, making sure only required instantiations are compiled, and using techniques like explicit instantiation.
In which scenarios could the use of goto be considered acceptable or even advisable?
- To enhance the readability of deeply nested loops.
- To replace exception handling mechanisms.
- For breaking out of multiple nested loops.
- To implement recursive functions.
While the use of "goto" is generally discouraged in modern programming due to making code harder to read and maintain, there are rare cases, like breaking out of multiple nested loops or complex error handling before exceptions were widely adopted, where its use might be considered.
In C++, _______ functions cannot be virtual.
- inline
- recursive
- overloaded
- default
Inline functions in C++ are expanded at the place where they are called, rather than being invoked. Because of this, they cannot be virtual as the virtual mechanism relies on function calls.
In what scenario might a program have a memory leak due to an exception being thrown?
- When the destructor isn't called
- When using global variables
- When an exception is caught and rethrown
- When exception specifications are used
A common memory leak scenario is when an exception is thrown before the memory allocated dynamically (usually with new) is deallocated. If the exception prevents a destructor or a delete statement from being reached, the memory is never released, resulting in a memory leak.
What is the primary purpose of using enum in C++?
- For iterating over collections
- For handling exceptions
- To create user-defined data types
- For memory management
The primary purpose of enum (short for "enumeration") in C++ is to create user-defined data types where you can define a set of named integer constants. It provides a way to assign names to integral constants, which makes a program easier to read and maintain.
You are developing a software library in C++ that will be used by other developers, and you want to ensure that the internal variables of your classes are not accessible while the methods are. How might encapsulation be implemented to achieve this while providing a clear API?
- Make all variables public and methods private.
- Make all methods and variables private.
- Make variables private and methods public.
- Only use static variables and methods.
Encapsulation is achieved by bundling data (variables) and methods that operate on the data into a single unit (class) and restricting the direct access to some of the object's components. In C++, this is implemented by declaring variables as private and providing public methods (API) to access and manipulate them.