Deck 11: Arrays, Addresses, and Pointers

Question 1

Pointers, both as variables and function parameters, are used to store addresses.

Answer 1

True

Question 2

Pointers are closely associated with array names.

Answer 2

True

Question 3

Offsets may be included in expressions using pointers.

Answer 3

True

Question 4

If gPtr is a pointer that points to the first element of an integer array (and each integer requires four bytes of storage), *(gPtr + 4 * 4) references the variable that is four integers beyond the variable pointed to by gPtr.

Question 5

When working with pointers and offsets, the correspondence between the number of bytes and number of variables is not handled by the compiler, so you must perform the conversions yourself.

Question 6

Any subscript used by a programmer is automatically converted to an equivalent pointer expression by the compiler.

Question 7

The parentheses in the pointer expression *(gPtr + 3) are not necessary to access the desired array element correctly.

Question 8

The expression *(gPtr + 3) changes the address stored in gPtr.

Question 9

A pointer constant is equivalent to a symbolic constant, in that the address stored in the pointer constant cannot be changed once it is set.

Question 10

Access to an array using a subscript can always be replaced by an equivalent access using the array name as a pointer.

Question 11

In every respect, an array name and a pointer can be used interchangeably.

Question 12

The address stored in the array name cannot be changed by an assignment statement.

Question 13

Attempting to assign the address of an array name is invalid.

Question 14

A pointer access can sometimes (but not always) be replaced using subscript notation.

Question 15

One advantage of using subscripts for array processing is that they are more efficient than using pointers directly.

Question 16

By adding numbers to and subtracting numbers from pointers, we can obtain different addresses.

Question 17

The addresses in pointers can be compared using any of the relational operators (==, !=, <, >, etc.) that are valid for comparing other variables.

Question 18

When adding or subtracting numbers to pointers, the computer automatically adjusts the number to ensure that the result still "points to" a value of the original data type.

Question 19

Addresses cannot be incremented or decremented using prefix or postfix increment and decrement operators.

Question 20

When initializing pointers you must be careful to set an address in the pointer.

Question 21

When an array is passed to a function, the array address is the only item actually passed.

Question 22

If nums is a two-dimensional integer array, *(*(nums + 2) + 1) refers to element nums[1][2].

Question 23

The following code is valid in C:
char *message;
strcpy(message,"abcdef");

Question 24

Instead of initially creating a string as an array it is possible to create a string using a pointer.

Question 25

The declaration char *seasons[4]; creates an array of four elements, where each element is a pointer to a character.

Question 26

&grade[3] is equivalent to ____; assume that grade is an array of integers, and each integer requires 4 bytes of storage..

A)&grade[0] + 3
B)&grade[0] + 4
C)&grade[0] + (3 * 4)
D)&grade[0] + (3 / 4)

Question 27

The address operator in C is ____.

A)&
B)*
C)->
D))

Question 28

The indirection operator in C is ____.

A)&
B)*
C)->
D))

Question 29

If we store the address of grade[0] in a pointer named gPtr (using the assignment statement gPtr = &grade[0];), then, the expression ____ references grade[0].

A)gPtr(0)
B)gPtr
C)&gPtr
D)gPtr

Question 30

The ____ in the expression *(gPtr + 1) is an offset.

A)*
B)gPtr
C)+
D)1

Question 31

If gPtr is a pointer that points to the first element of an integer array (and each integer requires four bytes of storage), ____ references the variable that is three integers beyond the variable pointed to by gPtr.

A)*gPtr + 3
B)*(gPtr + 3)
C)*(gPtr + 3 * 4)
D)*(gPtr + 3 / 4)

Question 32

When working with pointers, the ____ tells the number of variables that are to be skipped over.

A)indirection operator
B)address operator
C)offset
D)address

Question 33

The expression ____ adds 3 to "the variable pointed to by gPtr."

A)*(gPtr + 3)
B)*gPtr + 3
C)gPtr + 3
D)&gPtr + 3

Question 34

When an array is created, the compiler automatically creates an internal ____ for it and stores the base address of the array in it.

A)pointer constant
B)pointer
C)symbolic constant
D)location

Question 35

Assuming grade is an array of ten integers, the statement ____ is invalid.

A)grade = &grade[2];
B)*grade = *(grade + 2);
C)*grade = *grade + 2;
D)*grade = *(&grade[2]) + 2;

Question 36

If numPtr is declared as a pointer variable, the expression ____ can also be written as numPtr[i].

A)*numPtr + i
B)(numPtr + i)
C)*numPtr
D)*(numPtr + i)

Question 37

Pointers ____ be initialized when they are declared.

A)must
B)must not
C)can
D)cannot

Question 38

In performing ____ on pointers, we must be careful to produce addresses that point to something meaningful.

A)comparisons
B)arithmetic
C)subscript operations
D)duplication

Question 39

Consider the declarations
Int nums[100];
Int *nPtr;
The statement ____ produces the same result as nPtr = nums;.

A)nPtr = &nums[0];
B)nPtr = nums[0];
C)nPtr = *nums[0];
D)nPtr = &nums;

Question 40

Adding ____ to a pointer causes the pointer to point to the next element of the original data type being pointed to.

A)1
B)1 * sizeof(data type being pointed to)
C)2
D)2 * sizeof(data type being pointed to)

Question 41

Of the following expressions, ____ is the most commonly used. This is because such an expression allows each element in an array to be accessed as the address is "marched along" from the starting address of the array to the address of the last array element.

A)*ptNum--
B)*--ptNum
C)*ptNum++
D)*++ptNum

Question 42

int *ptNum = &miles; is ____.

A)always valid
B)never valid
C)only valid if miles is declared as an integer variable before ptNum is declared
D)only valid if miles is declared as an array of integers before ptNum is declared

Question 43

Consider the following declarations of a function that receives an array of integers and finds the element with the maximum value:
(i) findMax(int *vals, int numEls)
(ii) findMax(int vals[], int numEls)
The address in vals may be modified ____.

A)only if the function is declared as in (i)
B)only if the function is declared as in (ii)
C)if either (i) or (ii) is used
D)in neither case because an array variable cannot be modified (it is a pointer constant)

Question 44

If nums is a two-dimensional integer array, ____ refers to element nums[0][0].

A)*nums
B)*(*nums)
C)*(&nums)
D)&(*nums)

Question 45

If nums is a two-dimensional integer array, ____ refers to element nums[1][0].

A)*nums[1]
B)*nums[0]
C)*nums + 1
D)*nums++

Question 46

A suitable equivalent to the function header calc(int pt[2][3]) is ____.

A)calc(int *(*pt))
B)calc(int (*pt)[])
C)calc(int (*pt)[2])
D)calc(int (*pt)[3])

Question 47

The header line ____ declares calc to be a pointer to a function that returns an integer.

A)int *calc()
B)int (*calc)()
C)int &calc()
D)int calc(*)

Question 48

You can replace lines 5 and 6 in the following function with ____.
1 /* copy string2 to string1 */
2 void strcopy(char string1[], char string2[])
3 {
4 int i = 0;
5 while (string1[i] = string2[i])
6 i++;
7 }

A) while (*string1 = *string2) ;
B) while (*string1 = string2) ;
C) while (*string1++ = *string2++) ;
D) while (*++string1 = *++string2) ;

Question 49

After creating two variables as follows:
Char message1[81] = "this is a string";
Char *message2 = "this is a string";
The statement ____ is not valid in C.

A) message1 = "A new message";
C) message2 = message1;
B) message2 = "A new message";
D) message2[0] = 'T';