Deck 9: Pointers and Dynamic Arrays

Question 1

Write the code to declare a dynamic array of strings use the string pointer variable p1)that has as many elements as the variable arraySize.

Answer 1

p1 = new string[arraySize];

Question 2

Even though pointers point to addresses which are integers,you can not assign an integer to a pointer variable.

Answer 2

True

Question 3

Dynamically created variables have no name.

Answer 3

True

Question 4

A ___________ is the memory address of a variable.

Question 5

If p1 is an integer pointer variable,with the value of 1000,p1++ changes P1 to point to the memory location 1001.

Question 6

A pointer can be stored in an integer variable.

Question 7

Write the code that assigns to p1 an integer pointer variable)the pointer to a dynamically created integer.

Question 8

In the statement cout << *p1;,the * is called the ________________

Question 9

The & operator is called the _______________

Question 10

You can assign an array to a pointer variable.

Question 11

In the following statement,all the variables are pointers.
int* p1,p2;

Question 12

The size of dynamic arrays must be declared at compile time.

Question 13

Dynamic variables are created at __________

Question 14

When you return a dynamic array to the freestore,you must include the number of elements in the array.

Question 15

Write the code to return the dynamic memory pointed to by p1 to the freestore.

Question 16

If p1 and p2 are both pointers that point to integers in memory,the condition p1==p2 will be true if the values that are in those memory locations are the same.

Question 17

The size of a dynamic array is defined at ___________

Question 18

int *p1; declares a static variable.

Question 19

Declare a pointer variable named ptr to an integer.

Question 20

Dynamic variables are created from the ___________.

Question 21

If a program requires a dynamically allocate two-dimensional array,you would allocate the memory by using

A)p1 = new int*[numRows]; forint i=0; i < numRows; i++)
P1[i] = new int[numColumns];
B)p1 = new int*[numRows][numColumns];
C)p1 = new[numRows][numColumns]int;
D)none of the above

Question 22

Given that p1 is a pointer,p1++

A)always causes a run time error
B)advances p1 by one unit of the type of variable to which p1 points
C)adds 1 to whatever p1 is pointing to
D)adds one element to the array that p1 is pointing to

Question 23

Which of the following correctly declare 3 integer pointers?

A)int* p1,p2,p3;
B)int *p1,p2,p3;
C)int *p1,*p2,*p3;
D)all of the above.

Question 24

Which of the following is not true?

A)a pointer can be assigned the address of an array
B)an array can be assigned the value in a pointer variable
C)if a pointer points to an array,it can be used in place of the array name
D)if a pointer points to an array,the pointer does not know how many elements are in the array.

Question 25

Which of the following correctly declares a dynamic array of strings?

A)p1 = new string13);
B)p1 = new string[];
C)p1 = new string[13];
D)p1 = new stringArray13);

Question 26

Which of the following statements correctly prints out the value that is in the memory address that the pointer p1 is pointing to?

A)cout << &p1;
B)cout << p1;
C)cout << int* p1;
D)cout << *p1;

Question 27

In which case would you consider using a dynamic array?

A)If the array is small,and the size is known before the program runs.
B)If the program needs to get the size of the array from the user
C)If the array size is big,but known at compile time
D)You should always use a dynamic array

Question 28

Given that a typedef for IntPtr defines a pointer to an integer,what would be the correct declaration for a function that expects a reference to an integer pointer?

A)void f1 IntPtr& ptr);
B)void f1 IntPtr&* ptr);
C)void f1 IntPtr*& ptr);
D)All of the above

Question 29

Given that p1 is a pointer variable of the string class,which of the following are legal statements?

A)p1 = new int;
B)cout << *p1;
C)p1 = new char[10];
D)*p1 = new string;
E)B and D

Question 30

What is wrong with the following code fragment?
Int *p1,*p2;
P1 = new int;
P2 = new int;
*p1=11;
*p2=0;
P2=p1;
Cout << *p1 <<" " << *p2 << endl;
Delete p1;
Delete p2;

A)nothing
B)p1 and p2 both have the same value,so the delete p2 will cause an error
C)You have a memory leak.
D)B and C

Question 31

Which of the following assigns to p1 the pointer to the address of value?

A)*p1=&value;
B)p1=value;
C)p1=&value;
D)&p1 = *value;

Question 32

What is the output of the following code fragment?
Float *p1;
P1 = new float3);
Cout << *p1;

A)3.0
B)unknown,the address p1 points to is not initialized
C)unknown,the code is illegal,p1 points to a dynamic array
D)0.0

Question 33

Given that p1 is an integer pointer variable,and a1 is an integer array,which of the following statements are not legal code?

A)p1= a1;
B)cout << p1[0];
C)cin >> p1[0];
D)a1 = p1;

Question 34

Assuming that the pointer variable p1 is of the correct type and size is an integer with some value > 1,which of the following declarations are legal?

A)p1 = new string[size];
B)p1 = new ifstream[size];
C)p1 = new char[size*size];
D)A and B
E)A,B and C

Question 35

If p1 is an integer pointer that is pointing to memory location 1001,and an integer takes 4 bytes,then p1+1)evaluates to:

A)1002
B)1004
C)1005
D)Unknown

Question 36

Which of the following correctly declares a user-defined data type that defines a pointer to a float?

A)float* floatPtr ;
B)typedef float* floatPtr;
C)typedef floatPtr *float;
D)typedef floatPtr* float

Question 37

Which of the following statements correctly returns the memory from the dynamic array pointer to by p1 to the freestore?

A)delete [] p1;
B)delete p1[];
C)delete *p1;
D)delete p1;

Question 38

What is the output of the following code fragment?
Int v1=2,v2=-1,*p1,*p2;
P1 = & v1;
P2= & v2;
P2=p1;
Cout << *p2 << endl;

A)2
B)-1
C)-2
D)1

Question 39

What is the output of the following code?
Int *p1,*p2;
P1 = new int;
P2 = new int;
*p1=11;
*p2=0;
P2=p1;
Cout << *p1 <<" " << *p2 << endl;

A)11 0
B)0 11
C)11 11
D)0 0

Question 40

If two pointer variables point to the same memory location,what happens when one of the pointers is freed?

A)The other pointer should be considered to be un-initialized
B)The other pointer still points to a valid memory address
C)If you attempt to free the other pointer a run-time error will occur.
D)All of the above
E)A and C