Question 1

When a dynamic array with a class for a base type is declared,which constructor is called?
A)the copy constructor
B)the destructor
C)the default constructor
D)an explicit constructor

Accepted Answer

When a dynamic array with a class for a base type is declared, the default constructor is called for each element in the array.

Question 2

If obj1 and obj2 are both objects of a class that uses dynamic memory allocation,but the class does not have an assignment operator,what happens if you execute the following code?
Obj1=obj2;
A)A syntax error occurs,you can not assign one object to another object without the = operator
B)A run-time error occurs,because the C++ system does not know how to do the assignment.
C)The pointers)to the dynamically declared memory in obj2 are copied to the corresponding pointers in obj1.
D)There is a complete and independent copy of all the dynamic memory from obj2 to obj1

Accepted Answer

Since the class does not have an assignment operator, the default assignment operator provided by C++ will be used. This default operator performs a shallow copy, meaning it will simply copy the values of the pointers from obj2 to obj1. Therefore, the pointers to the dynamically declared memory in obj2 are copied to the corresponding pointers in obj1. This can lead to issues with memory management and potential memory leaks.

Question 3

The copy constructor for a class is called
A)when an object of the class is passed by value to a function.
B)when an object of the class is initialized by another object of the class
C)when a function returns an object of the class
D)all of the above

Accepted Answer

The copy constructor is invoked in all these scenarios: when an object is passed by value to a function, when an object is initialized by another object, and when a function returns an object of the class, potentially invoking copy elision optimization.

Question 4

Which of the following statements are true?
A)Array elements may be user-defined types structs or classes)
B)If a function is expecting a variable of the base type of the array,then you can pass an element of the array to the function.
C)All of the above.
D)None of the above.

Accepted Answer

Both statements A and B are correct. Arrays can contain user-defined types such as structs or classes, and elements of the array can be passed to functions expecting variables of the base type of the array.

Question 5

Which of the following are valid declarations for an assignment operator for a class named myClass?
A)void friend operator = myClass& left,const myClass& source);
B)void operator = myClass& left,const myClass& source);
C)void friend operator = const myClass& source);
D)void operator = const myClass& source);

Accepted Answer

The answer of Which of the following are valid declarations...

Question 6

Which of the following are not correct?
A)The destructor of a class is not named the same as the name of the class,but preceded with a tilde
B)The destructor of a class is not called when an object of the class goes out of scope
C)The destructor of a class is not a member of the class
D)The destructor of a class is a void function
E)all of the above

Accepted Answer

The destructor of a class is not a void function, it has no return type. The other statements are correct. The destructor is named with a tilde before the class name, is automatically called when an object goes out of scope, and is not a member function of the class.

Question 7

Which of the following statements are true?
A)A dynamic array can have a base type which is a class or a struct.
B)A class or a struct may have a member which is a dynamic array.
C)A and B
D)Neither

Accepted Answer

Both statements A and B are true. A dynamic array can have a base type which is a class or a struct. Similarly, a class or a struct may have a member which is a dynamic array. This is because dynamic arrays are essentially pointers to a block of memory, and pointers can point to objects and arrays of objects, including classes and structs.

Question 8

The destructor for a class is called
A)explicitly from the main program
B)when the class is instantiated
C)when the object of the class goes out of scope
D)Only at the end of main

Accepted Answer

The destructor for a class is called automatically when the object of the class goes out of scope. This happens when the object is destroyed, either because it goes out of scope or because it is deleted explicitly using the delete keyword. The other options listed (A, B, and D) are not correct because the destructor is not called explicitly by the main program or when the class is instantiated, and it may be called before the end of main if the object goes out of scope earlier.

Question 9

What happens when you define a class that used dynamic memory allocation and define a destructor but no copy constructor?
A)If an object of the class is plugged in for a call-by-value parameter,when the function ends,the parameter's dynamic memory is returned to the freestore at the end of the function execution.
B)When an object that was used as an argument for a call-by-value parameter goes out of scope,it will cause a run-time error.
C)It is possible to modify the values in the argument in the function.
D)All of the above
E)None of the above

Accepted Answer

The answer of What happens when you define a class...

Quiz 11: Friends, overloaded Operators, and Arrays in Classes

When a dynamic array with a class for a base type is declared,which constructor is called?

If obj1 and obj2 are both objects of a class that uses dynamic memory allocation,but the class does not have an assignment operator,what happens if you execute the following code? Obj1=obj2;

The copy constructor for a class is called

Which of the following statements are true?

Which of the following are valid declarations for an assignment operator for a class named myClass?

Which of the following are not correct?

Which of the following statements are true?

The destructor for a class is called

What happens when you define a class that used dynamic memory allocation and define a destructor but no copy constructor?