OOP in Object Oriented Programming : Practice MCQ Questions & Answers with Explanations

While returning an object we can use the copy constructor. When we assign the return value to another object of same class then this copy constructor will be used. And all the members will be assigned the same values as that of the object being returned.

When an object is passed to a function, actually its copy is made in the function. To copy the values, copy constructor is used. Hence the object being passed and object being used in function are different.

The restriction for copy constructor is that it must be used with the object of same class. Even if the classes are exactly same the constructor won’t be able to access all the members of another class. Hence we can’t use object of another class for initialization.

The copy constructor has the most basic function to initialize the members of an object with same values as that of some previously created object. The object must be of same class.

The object that has to be copied to new object must be previously created. The new object gets initialized with the same values as that of the object mentioned for being copied. The exact copy is made with values.

The references are made to object when the object is created and initialized with another object without calling any constructor. But the object pointer must be declared explicitly using symbol that will be capable of storing some address. Hence both are different.

The pointer should be declared as a const type. This prevents the pointer to change any value that is being pointed from it. This is a feature that is made to access the values using pointer but to make sure that pointer doesn’t change those values accidently.

The & symbol must be used. This should be done such that the object should be preceded by & symbol and then the address should be stored in another variable. This is done to get the address where the object is stored.

When the address pointed by the object pointer gets deleted, the pointer now points to an invalid address. Hence it becomes a dangling pointer. It can’t be null or void pointer since it doesn’t point to any specific location.

The pointer should be mentioned followed by the arrow operator. Arrow operator is applicable only with the pointers. Then the function name should be mentioned that is to be called.

The pointer to an object can hold only the addresses. Address of any other object of same class. This allows the programmer to link more than one objects if required.

The array name represents a pointer to the object. The name alone can represent the starting address of the array. But that also represents an array which is in turn stored in a pointer.

The pointers to an object can never access the private members of the class outside the class. The object can indirectly use those private members using member functions which are public in the class.

It is an implicit rule defined in most of the programming languages. It permits the programmer to declare a pointer to the derived class from a base class pointer. In this way the programmer doesn’t have to declare object for derived class each time it is required.

The object pointer can point to only one object at a time. The pointer will be able to store only one address at a time. Hence only one object can be referred.

The size of object pointer is same as that of any usual pointer. This is because only the address have to be stored. There are no values to be stored in the pointer.

The address of only the specified class type can get their address stored in the object pointer. The addresses doesn’t differ but they do differ for the amount and type of memory required for objects of different classes. Hence same class object pointer should be used.

This pointer denotes the object, in which it is being used. If member function is called with respect to one object then this pointer refers to the same object members. It can be used when members with same name are involved.

The members can be accessed from the object pointer by using arrow operator. The arrow operator can be used only with the pointer of class type. If simple object is declared, it must use dot operator to access the members.

The syntax must contain symbol after the className as the type of object. This declares an object pointer. This can store address of any object of the specified class.