Concepts Ch6-8, 10

Question 1

A class is a programmer-defined data type that describes what objects of the class will look like when they are created. * True * False

Answer 1

True

Question 1

A constant pointer is a pointer whose address value is constant. The value of the object at the address cannot be changed.

• True
• False

Answer 1

False. While a constant pointer is a pointer whose address value is constant, the value of the object at the address CAN be changed.

int * const ptr;

Question 3

A program statement outside of a class can access a private member. * True * False

Answer 3

False. A compiler error will result.

Question 3

A vector is a data type that allows you to store and manipulate 1D data.

• True
• False

Answer 3

True

Question 3

A float, string, structure, or a class can be referenced by an address.

• True
• False

Answer 3

True

Question 5

Arrays are automatically passed by reference.

• True
• False

Answer 5

True.

Caution: if you modify the array inside the function, you are modifying the actual data and any use of the array after the function returns will see the modifications made in the array.

Question 5

Array names are pointer constants.

• True
• False

Answer 5

True

Question 6

C++ allows a set of variables to be combined together into a single unit called a structure. * True * False

Answer 6

True

Question 6

Arrays of structures are handled the same way as arrays of objects.

• True
• False

Answer 6

True

Question 7

Class name and scope resolution operator (::) are an extension of the function name. When a function is defined outside the class declaration, you do not need to use the scope resolution operator. * True * False

Answer 7

False. When a function is defined outside of the class declaration, these must be present and must be located immediately before the function name in the function header.

Question 8

Constant pointers must be assigned an intial value when created.

• True
• False

Answer 8

True

Question 9

Constant pointers to constants make the address in the pointer constant and the value of what it points to constant.

• True
• False

Answer 9

True

Question 10

Declaring function parameters as pointers is another way to pass objects by reference.

• True
• False

Answer 10

True

Question 11

How are member of a structure accessed?

Answer 11

With the dot operator.

Question 12

How are structures passed by default? * by value * by reference * by constant reference

Answer 12

Passed by value. A copy of the entire original structure is made and passed to the function.

Question 13

How can you avoid dangling pointers?

Answer 13

By setting the pointer to NULL after you call delete on the pointer.

Question 14

How can you increase the size of a vector after it has been initially declared?
vectormyVector(10);

Answer 14

1. You can add values to the end of the vector by calling the push_back function.
   myVector.push_back(1.23);
2. You can increase the size by calling the resize function.
   myVector.resize(20)

Question 15

How should structures be passed by normally and what does it do for the function? * by value * by reference * by constant reference

Answer 15

Passed to functions by reference, which allows the function to access the member variables of the original structure, allowing it to change them.

Question 16

If a function needs to store or change data in an object’s member variables, the object must be passed to it by value. * True * False

Answer 16

False. It must be passed to it by reference.

Question 17

If the pointer is a pointer to a constant, you can use the indirection operator (*) or the structure pointer indirection operator (->) on the left side of an assignment statement.

• True
• False

Answer 17

False. You cannot use the * or -> operators on the left side of assignment statement.

Question 19

If you do not need to modify the array in a function, you should not use the const keyword in the function declaration.

• True
• False

Answer 19

False. You should use the const keyword. This can prevent you from accidentally modifying the array values.

Question 19

In an array, the name of an array variable is not a pointer.

• True
• False

Answer 19

False

Question 20

Pointer variables never store an address.

• True
• False

Answer 20

False

Question 21

To compare the contents of an array, what must you do?

Answer 21

You must compare their individual elements.

Question 23

To declare a function with a 2D array parameter, you must specify the size of the second dimension: void function2D(int[][31] monthDayData); * True * False

Answer 23

True

Question 24

To use any data type, what 2 things do you need to know?

Answer 24

What values it can hold What operations apply to it

Question 25

To use vectors, your program header does not need to indicate that you are using namespace std. * True * False

Answer 25

False. You need to include namespace std.

Question 26

Using the indirection operator (\*) allows you to dereference the pointer. * True * False

Answer 26

True

Question 27

What are 4 differences in the way a structure is declared to the way a class is declared?

Answer 27

the keyword struct is used instead of class \* structures rarely include member functions, normally declaration only declares member variables \* declarations normally do not include access specifiers public or private \* members of structure default to being public

Question 28

What do the following decrement operators do to the array? * amount[count]--; * amount[count--];

Answer 28

* amount[count]--; decrements the value stored in amount[count] * amount[count--]; decrements the variable count, but does nothing to the value stored in amount[count]

Question 29

What do the following vector member functions do? * vectorName.size() * vectorName.pop\_back() * vectorName.clear()

Answer 29

* vectorName.size() - returns the number of elements in the vector * vectorName.pop\_back() - removes the last element of vectorName * vectorName.clear() - Clears a vector of all its elements

Question 30

What do you use to access individual elements of the array?

Answer 30

Subscripts.

Question 32

What does the vector function pop\_back do?

Answer 32

The function pop\_back is useful for removing the last element of the vector, and decreasing the size by one.

Question 33

What is an accessor function?What is a mutator function?

Answer 33

An accessor function uses the value of a class variable, but does not change it. Commonly known as get/getter functions because they just retrieve or use the value.A mutator function stores a value in a member variable or changes its value. Commonly known as set/setter functions because they set the value of a class variable.

Question 33

What does this return? float\* myBigNumbers = new float(3);

Answer 33

This returns a pointer to a section of memory with space for 3 type float objects. (12 total bytes)

Question 34

What is the difference between the array size declarator and a subscript?

Answer 34

The number inside the brackets in an array definition is the size declarator and it specifies how many elements the array holds. The number inside the brackets in an assignment statement is a subscript and it specifies which element is being accessed.

Question 36

What is the difference when an array holding numeric values is defined globally and when it is defined locally?

Answer 36

When defined globally, all of its elements are initialized to zero by default. Local arrays, however, have no default initialization value.

Question 37

What is the primary advantage of a vector over a 1D array?

Answer 37

Vectors are not fixed in size or length. You can add items to the end of the vector and the vector will automatically allocate more memory if needed to store the new item.

Question 38

What is the purpose of a class declarator?What is each object created called?

Answer 38

To describe what the objects created from the class will look like when they are constructed.Each object created from it is called an instance of a class, and defining a class object is called instantiating the class.

Question 39

What is the subscript of the last element in the array?

Answer 39

The subscript of the last element in the array is one less than the total number of elements in the array.

Question 40

What makes a union unique to a structure?

Answer 40

All member variables occupy the same memory area, so only one member can be used at a time. Unions conserve memory by storing all of their members in the same memory location.

Question 41

What operator is used to get the address of a variable.

Answer 41

The & (address) operator.

Question 42

When declaring pointer variables, never initialize them to NULL. * True * False

Answer 42

False, unless assigning an address during the declaration statement.

Question 43

When do you use the const keyword?

Answer 43

When you want to define a variable or a value that cannot be changed.

Question 44

When specifying a starting size for a vector, the size declarator is enclosed in square brackets. * True * False

Answer 44

False. It is enclosed in parentheses.

Question 45

When specifying higher dimensional arrays as parameters for functions, you must define the size of every dimension. * True * False

Answer 45

False. You must define the size of every dimension EXCEPT the first dimension.

Question 46

When using the new operator for dynamic memory allocation, the left side of the assignment operator must never be a pointer variable. * True * False

Answer 46

False. Always because the new operator returns the memory address of the space it has allocated for the new object.

Question 48

When you dereference a pointer, your program gets a copy of the actual object. * True * False

Answer 48

False. Program gets the actual object at the adress, not a copy.

Question 48

When you add or subtract from a pointer, you move the pointer forward or backwards by an amount equal to the size of type of the object that pointer points to. * True * False

Answer 48

True

Question 50

Which has a higher operator predecedence? * \* operator * "." operator

Answer 50

"." operator. Which requires the use of parentheses around the dereferencing operator.

Question 51

Which is the correct way to compare a structure? \* if (employee1.hours == employee2.hours) \* if (employee1 == employee2

Answer 51

if (employee1.hours == employee2.hours)

Question 52

Which of the following are true about destructors? \* have no return type \* cannot accept arguments \* there can only be one destructor

Answer 52

All are true.

Question 53

Which of the following initialization statements are valid? * int numbers[7] = {1, 2, 3, 4, 5, 6, 7, 9}; * int numbers[7] = {1, , 4, , 3, 5, 7};

Answer 53

Neither. They are both illegal. The initialization list cannot have more values than the array can hold. and If you leave an element uninitialized, you must leave all the elements that follow it uninitialized as well.

Question 54

Which pointer declaration is invalid? * double \*myDoublePointer; * double\* myDoublePointer2; * double \* myDoublePointer3;

Answer 54

None. They are all valid.

Question 55

Which vector declaration is valid? * vector exampleVector; * vector exampleVector(10); * vector exampleVector(10, 2); * vector vectorOne(10, 2); vector vectorTwo(vectorOne);

Answer 55

All four are valid.

Question 56

You can add data into an array by using the initializer method at any time. * True * False

Answer 56

False. The initializer method can only be used at the time you declare the array.

Question 57

You can enter or get data from an array in any order. * True * False

Answer 57

True

Question 58

You can only use the -\> operator with structure pointers or class pointers. * True * False

Answer 58

True.

Question 59

You define a pointer to a constant when you want the pointer to point to an object that cannot or should not be changed. What happens in this case? const double \*rates;

Answer 59

rates is a pointer to a constant double or rates points to a constant double and The address of a variable must be assigned to the pointer to a constant.

Question 60

You do not need to specify an initialization list when you leave out the size declarator. * True * False

Answer 60

False. If you leave out the size declarator, you must specify an initialization list.