Deck 10: Pointers

Question 1

A pointer may be initialized with

A) the address of an existing object of the appropriate type.
B) the value of a floating-point constant.
C) the value of a floating-point variable.
D) All of the above
E) None of the above

Answer 1

A

Question 2

With pointer variables, you can ________ manipulate data stored in other variables.

A) never
B) seldom
C) indirectly
D) All of the above
E) None of the above

Answer 2

C

Question 3

Memory cannot be allocated after a program is already running.

Answer 3

False

Question 4

With pointer variables you can access, but you cannot modify, data in other variables.

Question 5

The term pointer can be used interchangeably with

A) address.
B) variable.
C) decimal pointer.
D) counter pointer.
E) None of the above

Question 6

Assuming that arr is an array identifier, the statement sum += *arr;

A) is illegal in C++.
B) will always result in a compiler error.
C) adds the value stored in arr[0] to sum.
D) adds the address of the pointer arr to sum.
E) None of the above

Question 7

An array name is a pointer constant because the address it represents cannot be changed during run-time.

Question 8

Which of the following statements correctly deletes a dynamically-allocated array pointed to by p?

A) delete p;
B) p delete[ ];
C) delete [ ] p;
D) delete array p;
E) None of the above

Question 9

When the less than ( < ) operator is used between two pointer variables, the expression is testing whether

A) the value pointed to by the first is less than the value pointed to by the second.
B) the value pointed to by the first is greater than the value pointed to by the second.
C) the address of the first variable comes before the address of the second variable in the computer's memory.
D) the first variable was declared before the second variable.
E) None of the above

Question 10

A pointer with the value 0 (zero) is called the NULL pointer.

Question 11

________ can be used as pointers.

A) Array names
B) C++ string objects
C) Punctuation marks
D) All of the above
E) None of the above

Question 12

The delete operator should only be used on pointers that

A) have not yet been used.
B) have been correctly initialized.
C) point to storage allocated by the new operator.
D) are appropriately dereferenced.
E) None of the above

Question 13

Which arithmetic operations can be performed on pointers?

A) All arithmetic operations that are legal in C++
B) Multiplication, division, addition, and subtraction
C) Addition , subtraction , preincrement, and postincrement
D) Only multiplication and addition
E) None of the above

Question 14

It is legal to subtract a pointer variable from another pointer variable.

Question 15

When you work with a dereferenced pointer, you are actually working with

A) a variable whose memory has been deallocated.
B) a copy of the value pointed to by the pointer variable.
C) the variable whose address is stored in the pointer variable.
D) All of the above
E) None of the above

Question 16

Which of the following statements is not valid C++ code?

A) int ptr = &num1;
B) int ptr = int *num1;
C) float num1 = &ptr2;
D) All of the above are valid.
E) All of the above are invalid.

Question 17

The statement double *num;

A) defines a variable of type double called num.
B) defines and initializes a pointer variable called num.
C) initializes a variable called *num.
D) defines a pointer variable called num.
E) None of the above

Question 18

The ________, also known as the address operator, returns the memory address of a variable.

A) asterisk ( * )
B) ampersand ( & )
C) percent sign (%)
D) exclamation point ( ! )
E) None of the above

Question 19

A function may return a pointer, but the programmer must ensure that the pointer

A) is pointing to an object that is still valid after the return of the function.
B) has been assigned an address.
C) was received as a parameter by the function.
D) has not previously been returned by another function.
E) None of the above

Question 20

The code segment int *ptr; has the same meaning as

A) int ptr;.
B) *int ptr;.
C) int ptr*;.
D) int* ptr;.
E) None of the above

Question 21

A pointer variable is designed to store

A) any legal C++ value.
B) only floating-point values.
C) a memory address.
D) an integer.
E) None of the above

Question 22

The statement cout << *ptr; will output

A) the value stored in the variable whose address is contained in ptr.
B) the string "*ptr".
C) the address of the variable stored in ptr.
D) the address of the variable whose address is stored in ptr.
E) None of the above

Question 23

A pointer with the value 0 (zero) is called the NULL pointer.

Question 24

Any arithmetic operation may be performed on pointers.

Question 25

A pointer can be passed as an argument to a function.

Question 26

The expression s->m is meaningful only when s is a pointer to a structure and m is a member of the structure.

Question 27

The statement shared_ptr p(new int); involves

A) a single allocation of a dynamic block of memory.
B) two allocations of two different dynamic blocks of memory.
C) three allocations of three different dynamic blocks of memory.
D) no allocations of dynamic memory.
E) None of the above

Question 28

The statement cout << &num1; will output

A) the value stored in the variable called num1.
B) the memory address of the variable called num1.
C) the number 1.
D) the string "&num1".
E) None of the above

Question 29

The expression s->m has the same meaning as (*s).m.

Question 30

C++ does not perform array bounds checking.

Question 31

When the ________ is placed in front of a variable name, it returns the address of that variable.

A) asterisk ( * )
B) conditional operator
C) ampersand ( & )
D) semicolon ( ; )
E) None of the above

Question 32

If arr is an array identifier and k is an integer, the expression arr[k] is equivalent to

A) *(arr + k).
B) *arr + k.
C) &arr[k].
D) arr + k.
E) None of the above

Question 33

Suppose that a function dynamically allocates a block of memory with a local pointer variable p pointing to the allocated block. Suppose further that there are no other pointers referencing that block of memory, and the function returns without doing a delete on p. Then

A) the pointer p becomes a dangling pointer.
B) the compiler will automatically deallocate the memory pointed to by p.
C) the program will suffer from memory leaks.
D) the returning function will throw the bad_alloc exception.
E) None of the above

Question 34

The statement int *ptr; means

A) the variable called ptr will store an integer value.
B) the variable called *ptr will store an asterisk and an integer value.
C) ptr is a pointer variable that will store the address of an integer variable.
D) All of the above
E) None of the above

Question 35

The set of operations supported by the unique_ptr class include

A) the dereferencing operators * and ->, the post and pre increment operators ++, and the post and pre decrement operators --.
B) the dereferencing operators * and ->.
C) the assignment operator.
D) the delete operator.
E) None of the above

Question 36

Which of the following statements is not valid C++ code?

A) int ptr = &num1;
B) int ptr = int *num1;
C) float num1 = &ptr2;
D) All of the above are valid.
E) All of the above are invalid.

Question 37

You may use the type pointer to a structure as the type of a

A) function parameter.
B) structure member.
C) function return type.
D) All of the above
E) None of the above

Question 38

To dereference a structure pointer and simultaneously access a member of the structure, the appropriate operator to use is

A) the ampersand, &.
B) an asterisk, *.
C) the structure pointer operator, ->.
D) the dereference operator, <-.
E) None of the above

Question 39

A function may return a pointer, but the programmer must ensure that the pointer

A) is pointing to an object that is still valid after the return of the function.
B) has been assigned an address.
C) was received as a parameter by the function.
D) has not previously been returned by another function.
E) None of the above

Question 40

The ________ and ________ operators can respectively be used to increment and decrement a pointer variable.

A) dereferencing, indirection
B) modulus, division
C) ++, --
D) All of the above
E) None of the above

Question 41

If Circle is a structure type, the statement Circle *pcirc;

A) defines a structure variable called *pcirc.
B) defines a structure pointer called pcirc.
C) is illegal in C++.
D) initializes a Circle pointer.
E) None of the above

Question 42

It is possible for a structure to contain as a member a pointer to its own structure type.

Question 43

A reason for passing a pointer to a function is

A) to avoid the overhead of copying large data structures.
B) to allow the called function to modify a variable accessible to the calling function.
C) to allow easy access to data in the function that is being called.
D) A and B are both True.
E) None of the above

Question 44

Every byte in the computer's memory is assigned a unique

A) value.
B) address.
C) dynamically allocated value.
D) name.
E) None of the above

Question 45

The statement Rectangle * boxPtr; defines a variable boxPtr to be a pointer pointing to a type Rectangle.

Question 46

A statement that displays the address of the variable num1 is

A) cout << num1;.
B) cout << *num1;.
C) cout << &(*num1);.
D) cout << &num1;.
E) None of the above

Question 47

A dangling pointer is a pointer

A) to a block of memory that has been deleted.
B) that has been declared, but has not yet been assigned a value.
C) that has not been initialized.
D) that has been assigned the value of null or null_ptr.
E) None of the above

Question 48

When the ________ is placed in front of a variable name, it returns the address of that variable.

A) asterisk ( * )
B) conditional operator
C) ampersand ( & )
D) semicolon ( ; )
E) None of the above

Question 49

The statement cin >> *p;

A) stores the keyboard input into the variable p.
B) stores the keyboard input into the pointer called p.
C) is illegal in C++.
D) stores the keyboard input into the variable pointed to by p.
E) None of the above

Question 50

The statement int *ptr = new int; acquires memory to hold an integer and then

A) initializes the allocated memory to 0.
B) assigns an integer value to the variable called ptr.
C) sets ptr to point to the allocated memory.
D) creates a new pointer called int.
E) None of the above

Question 51

Which of the following statements correctly deletes a dynamically-allocated array pointed to by p?

A) delete p;
B) p delete[ ];
C) delete [ ] p;
D) delete array p;
E) None of the above

Question 52

If dynamically allocated memory is not freed,

A) the system may run out of memory.
B) it results in a compiler error.
C) a run-time error informs your user that the program did not free memory space.
D) the source code will not link correctly.
E) None of the above

Question 53

If s is a structure variable and p, a pointer, is a member of the structure, the statement cout << *s.p; will

A) output the dereferenced value pointed to by p.
B) result in a compiler error.
C) output the address stored in p.
D) output the value stored in s.
E) None of the above

Question 54

An array name is a pointer constant because the address it represents cannot be changed during run-time.

Question 55

Any time you use the new operator, it is good practice to

A) use delete afterwards to free the memory allocated by new.
B) use a preprocessor directive.
C) clear the data from the old operator
D) All of the above
E) None of the above

Question 56

A pointer variable may be initialized with

A) any non-zero integer value.
B) the address of an existing variable of the appropriate type.
C) A and B are both True.
D) None of the above

Question 57

If a variable occupies more than one byte of memory, its address is

A) the address of the last byte of storage allocated to it.
B) the average of the addresses used to store the variable.
C) the address of the first byte of storage allocated to it.
D) general delivery.
E) None of the above

Question 58

The expression *s->p; is only meaningful if s is a pointer to a structure and p is a pointer that is a member of that structure.

Question 59

The ampersand (&) is used to dereference a pointer variable in C++.

Question 60

Dynamic memory allocation occurs

A) when a variable is created by the compiler.
B) when a variable is created at run-time.
C) when a pointer fails to dereference the right variable.
D) when a pointer is assigned an incorrect address.
E) None of the above

Question 61

A temporary value in a program can be referred to by at most one lvalue reference.

Question 62

A ________________ keeps track of dynamically-allocated memory and automatically deletes when it is no longer in use.

A) deleting pointer
B) null pointer
C) smart pointer
D) memory conservation pointer
E) None of the above