The goto statement can lead to _______ if used indiscriminately.
- spaghetti code
- infinite loop
- syntax error
- recursion
Using the goto statement without careful consideration can lead to "spaghetti code", which is a term for code that is tangled and difficult to follow or maintain due to excessive jumps.
How can you prevent users from mistakenly instantiating your template classes with non-numerical types in a C++ library of numerical methods, leading to confusing compiler errors?
- Provide runtime type checking
- Use static_assert with type traits
- Offer detailed documentation
- Implement virtual functions
The static_assert mechanism, combined with type traits, allows for compile-time checks. By using static_assert along with type traits like std::is_arithmetic, it's possible to generate clear, intentional compiler errors if a user tries to instantiate a template with a non-numeric type, thus providing instant feedback to the user.
Which data type would be most appropriate for storing a boolean value?
- int
- char
- double
- bool
The bool data type is specifically designed in C++ to store boolean values, which can be either true or false. Using other data types like int, char, or double for boolean values would be inefficient and not semantically clear. Thus, bool is the most appropriate choice for this purpose.
How can a function indicate that it will not throw any exceptions?
- By using the noexcept specifier
- By returning a null pointer
- By using the try block without catch
- By marking it as static
The noexcept specifier in C++11 and later indicates that a function does not throw exceptions. If such a function does throw an exception, the program will terminate (usually by calling std::terminate). This can be a useful optimization hint for the compiler.
In C++, the data type _______ is commonly used to store large integers.
- float
- char
- long long int
- double
In C++, the long long int data type is designed to store very large integers. It can typically store at least 64 bits, allowing for a wide range of integer values far beyond the standard int.
How does a range-based for loop work in C++11 and above?
- It works only on arrays and not on containers.
- It iterates over elements using indices.
- It allows iterating over all elements in a container or array directly.
- It requires manual initialization of iterators.
In C++11 and newer versions, the range-based for loop provides a more readable syntax to iterate over all elements of a container or an array. The loop automatically gets the begin and end iterators of the range and iterates over each element without needing manual indexing.
The members of a struct are _______ by default.
- private
- public
- protected
- static
In C++, the members of a structure (struct) are public by default. This means they can be accessed from functions outside the structure. This is in contrast to the members of a class, which are private by default and cannot be accessed or viewed outside of the class.
Which parameter-passing method does not allow the function to modify the actual argument?
- By value
- By reference
- By pointer
- By name
When parameters are passed by value, a copy of the argument is made for the function. Any modifications to this copy do not affect the original argument outside the function.
How does C++ handle the virtual table in a multiple-inheritance scenario?
- Single table for all classes
- Separate tables for each base class
- A combination of both depending on visibility
- Virtual tables are not used
In C++, when a class inherits from multiple base classes, each base class will have its own virtual table. Thus, an object of the derived class will have separate virtual tables for each inherited class to handle dynamic dispatch for function calls, ensuring correct method resolution.
You are tasked with enhancing the performance of a critical path in an application. You identify a function that is called very frequently as a potential optimization target. Which specific aspect of the return statement could you focus on to possibly improve performance, especially considering modern C++ standards?
- Returning by value.
- Returning by pointer.
- Using return in a loop to optimize iterations.
- Returning by reference or moving.
In modern C++, when considering performance-critical paths, it's beneficial to understand the difference between returning by value and returning by reference or using move semantics. Especially with the advent of Rvalue references in C++11, returning by reference or moving can avoid unnecessary copies and lead to significant performance improvements. Returning by pointer is less idiomatic and might not convey ownership semantics clearly.