What is the correct syntax for declaring a function that returns an integer?
- int functionName;
- functionName: int;
- int functionName()
- int: functionName()
In C++, to declare a function that returns an integer, the correct syntax is "int functionName()". The type "int" signifies that the function's return type is an integer, and the parentheses "()" indicate it's a function declaration. Actual implementation or body of the function would follow the declaration.
In C++11 and later, the keyword _______ can be used in a range-based for loop to avoid copying elements.
- const
- mutable
- auto
- static
In C++11's range-based for loop, the const keyword ensures that elements are not modified, effectively preventing unintentional copies or modifications to the elements.
What is the potential problem with the following loop: while(true) { /* code */ }?
- It will cause a compile-time error.
- It can potentially result in an infinite loop.
- The code inside will never execute.
- It will slow down the computer significantly.
The loop while(true) will continue to execute indefinitely since the condition is always true. This can potentially lead to an infinite loop, consuming CPU resources, and making the program unresponsive unless externally interrupted.
You are designing a class that will be widely used across a large project. The class will often be copied and assigned to other instances. What considerations related to constructors and assignment operators should be taken into account to ensure efficient and correct operation?
- Use of shallow copy.
- Implementing move semantics.
- Avoid using constructors.
- Only use private member variables.
When a class is frequently copied or assigned, it's crucial to consider the efficiency of these operations. Move semantics, introduced in C++11, allow resources to be "moved" from one object to another, without making a copy. This can greatly improve performance. Shallow copy can lead to issues like double deletion, and avoiding constructors or only using private members doesn't address the efficiency of copying or assignment.
Which of the following best describes the concept of abstraction in C++?
- Hiding complex reality while exposing only the necessary.
- Protecting data from unauthorized access.
- Using single inheritance.
- Creating multiple instances of an object.
Abstraction in C++ refers to the concept of hiding the complicated reality of an object while only exposing operations relevant for that object. This allows for simplifying complex systems by breaking them down into smaller, more manageable parts, enabling developers to focus on high-level functionalities.
When a function is called recursively, each call creates a new set of the function's _______.
- variables
- loops
- conditions
- headers
Each recursive call creates a new set of the function's local variables. This is maintained in what's called the call stack, where each call has its own memory space.
Some compilers detect tail recursion and optimize it through a technique known as _______.
- tail-call optimization
- loop unrolling
- inline expansion
- code compression
Tail-call optimization (or TCO) is a technique where the compiler replaces a function's tail call (a recursive call that's the last thing the function does) with a jump instruction, essentially converting the recursion into iteration and thereby avoiding new stack frame creation.
Which of the following operators cannot be overloaded in C++?
- ==
- =
- ::
- ++
In C++, most of the operators can be overloaded with a few exceptions. Among the operators that cannot be overloaded are: the scope resolution operator ::, the member selection operators . and .*, and the ternary conditional operator ?:.
What is the impact of template metaprogramming on compile-time and runtime?
- Increases both compile-time and runtime.
- Reduces compile-time but increases runtime.
- Increases compile-time but reduces or has no impact on runtime.
- It doesn't affect compile-time or runtime.
Template metaprogramming (TMP) shifts computations to the compile-time, making the generated code more optimized. This results in increased compile times because the computations and code generation are happening at that phase. However, at runtime, the program may run faster or at least not have an added overhead from TMP since the computations were already done during compilation.
When trying to conserve memory usage, which method of parameter passing might be most effective in certain situations?
- Pass by value
- Pass by pointer
- Pass by array
- Pass by double reference
Passing by pointer often conserves memory because only the address of the variable (usually 4 or 8 bytes, depending on the architecture) is passed, regardless of the size of the actual data. While pass by value creates a copy of the actual data, which can consume more memory, especially for large objects or structs. Pass by reference behaves similarly to pass by pointer in this regard.