Cpp Interview Questions and Answers

Answer: - Simplified view of an object in user’s language is called abstraction. - It is the simplest, well-defined interface to an object in OO and C++ that provides all the expected features and services to the user in a safe and predictable manner. - It provides all the information that the user requires. - Good domain knowledge is important for effective abstraction. - It separates specifications from implementation & keeps the code simpler and more stable.

Answer: No, the real purpose of a class is not to export data. Rather, it is to provide services. Class provides a way to abstract behaviour rather than just encapsulating the bits. b.) What things would you remember while making a interface? - A class’s interface should be sensible enough. It should behave the way user expects it to. - It should be designed from the outside in.

Answer: The biggest benefits of proper inheritance are : a.) substitutability and b.) extensibility. Substitutability – The objects of a properly derived class can be easily and safely substituted for an object of its base class. Extensibility – The properly derived class can be freely and safely used in place of its base class even if the properly derived class is created a lot later than defining the user code. Extending the functionalities of a system is much easier when you add a properly derived class containing enhanced functionalities.

Answer: Many projects meet a dead end because of bad inheritance. So, it certainly has the potential to wreck a project. Small projects still have a scope to avoid the complete consequence of bad inheritance if the developers communicate and co-ordinate with an easy system design. This kind of a luxury is not possible in big projects, which means that the code breaks in a way difficult and at times impossible way to fix it.

Answer: - The runtime errors in C++ can be handled using exceptions. - This exception handling mechanism in C++ is developed to handle the errors in software made up of independently developed components operating in one process and under synchronous control. - According to C++, any routine that does not fulfil its promise throws an exception. The caller who knows the way to handle these exceptions can catch it.

Answer: A function should throw an exception when it is not able to fulfil its promise. As soon as the function detects a problem that prevents it from fulfilling its promise, it should throw an exception. If the function is able to handle the problem, recover itself and deliver the promise, the exception should not be thrown. If an event happens very frequently then exception handling is not the best way to deal with it. It requires proper fixation.