Mastering C++: A Comprehensive Quiz Based on 'Thinking in C++'

What does the virtual function mechanism allow?

1. Faster execution of the function

2. Function overloading

3. Late binding based on the object type at runtime

4. Multiple function definitions with the same name

The correct answer is: Late binding based on the object type at runtime

The virtual function mechanism in programming languages such as C++ allows for dynamic binding, which means that the specific function to be executed is determined at runtime based on the object type, rather than at compile time. This allows for greater flexibility and polymorphism in the code, as different subclasses can have their own implementations of the same function. Options A, B, and D do not accurately describe the main purpose of the virtual function mechanism. Option A is incorrect because the execution speed of a function is not directly affected by the virtual function mechanism. Option B is incorrect because function overloading is a separate concept, where multiple functions with the same name but different parameters can exist. Option D is incorrect because it is not unique to the virtual function mechanism, as other programming techniques such as function overloading and templates also allow for multiple function definitions with the same name.