Reliance Jio C++ Programming Quiz-1

In C++, if we do not write our own, then compiler automatically creates a default constructor, a copy constructor and a assignment operator for every class.

In C++, a structure is same as class except the following differences:

1) Members of a class are private by default and members of struct are public by default.
2) When deriving a struct from a class/struct, default access-specifier for a base class/struct is public. And when deriving a class, default access specifier is private.

Every object maintains a copy of non-static data members. For example, let Student be a class with data members as name, year, batch. Every object of student will have its own name, year and batch. On a side note, static data members are shared among objects. All objects share codes of all methods. For example, every student object uses same logic to find out grades or any other method.

Inline functions are generally used in place of small macros. They are substitute to macros and better than macros

In C++, a Copy Constructor may be called in following cases:
1. When an object of the class is returned by value.
2. When an object of the class is passed (to a function) by value as an argument.
3. When an object is constructed based on another object of the same class.
4. When compiler generates a temporary object.

Virtual function is can't be static in C++.

In C++ class template and function template are similar in the way the are initiated. Class template are not used for storage class. Class templates and function templates are instantiated in the same way and Class template is not initiated by defining an object using the template. So (2), (3), (4) are not correct in C++.

Header file can not be passed to a function in C++. While array, constant and structure can be passed into a function.

There is error in fun2(). It is a static function and tries to access this pointer. this pointer is not available to static member functions as static member function can be called without any object.

Currently there is no PrepInsta Explanation. Did you know?

You can also submit your own version of explanations under user explanation section and also view other submitted explanations by other users.

Since b1 and b2 both inherit from class base, two copies of class base are there in class derived. This kind of inheritance without virtual causes wastage of space and ambiguities. virtual base classes are used to save space and avoid ambiguities in such cases.

The statements which may cause problems are put in try block. Also, the statements which should not be executed after a problem accursed, are put in try block. Note that once an exception is caught, the control goes to the next line after the catch block.

In object-oriented programming, in languages such as C++, and Object Pascal, a virtual function or virtual method is an inheritable and overridable function or method for which dynamic dispatch is facilitated. This concept is an important part of the (runtime) polymorphism portion of object-oriented programming (OOP). In short, a virtual function defines a target function to be executed, but the target might not be known at compile time.

In C++, all types (including primitive and pointer) can be thrown as exception. But in Java only throwable objects (Throwable objects are instances of any subclass of the Throwable class) can be thrown as exception. There is a special catch called “catch all” that can catch all kind of exceptions.

cout is an object of ostream class which is a compiler defined class. When we do "cout << obj" where obj is an object of our class, the compiler first looks for an operator function in ostream, then it looks for a global function. One way to overload insertion operator is to modify ostream class which may not be a good idea. So we make a global method.

When a function returns by reference, it can be used as lvalue. Since x is a static variable, it is shared among function calls and the initialization line \"static int x = 10;\" is executed only once. The function call fun() = 30, modifies x to 30. The next call \"cout << fun()\" returns the modified value.

A member function can access it's class member variables, irrespective of the access specifier in which the member variable is declared.So, a member function can always access the data in the class of which it is a member.

1. ios:app -> All output operations are performed at the end of the file, appending the content to the current content of the file.
2.ios::out -> Open for output operations.
3.ios::in -> Open for input operations.

The member function is_open can be used to determine whether the stream object is currently associated with a file.

<fstream> header file contains all the file reading and writing functions. Also <ifstream> and <ofstream> contains functions only reading and only writing to files related functions respectively.