Concepts Review Ch 4-8, 10

Question 1

Precedence of relational operators:

> >= <

== !=

• True
• False

Answer 1

True

Question 1

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

• True
• False

Answer 1

True

Question 1

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

• True
• False

Answer 1

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

Question 1

Which vector declaration is valid?

• vector exampleVector;
• vector exampleVector(10);
• vector exampleVector(10, 2);
• vector vectorOne(10, 2);
  vector vectorTwo(vectorOne);

Answer 1

All four are valid.

Question 2

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

Answer 2

When defined globally, all of its elements are initialized to zero by default.

Local arrays, however, have no default initialization value.

Question 4

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

Answer 4

1. What values it can hold
2. What operations apply to it

Question 5

When an argument is passed into a parameter by _____, only a copy of the argument’s value is passed. Changes to the parameter do not affect the original argument.

Answer 5

value

Question 5

How can you avoid dangling pointers?

Answer 5

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

Question 5

Which of the following are true about destructors?

• have no return type
• cannot accept arguments
• there can only be one destructor

Answer 5

All are true.

Question 6

When would you use a for loop?

Answer 6

Ideal in situations where the exact number of iterations is known.

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

Which pointer declaration is invalid?

• double *myDoublePointer;
• double* myDoublePointer2;
• double * myDoublePointer3;

Answer 8

None. They are all valid.

Question 9

What is a mutator function?

Answer 9

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 10

What is an accessor function?

Answer 10

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.

Question 11

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 11

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

Question 12

A function cannnot send a value back to the part of the program that called the function.

• True
• False

Answer 12

False.

Question 12

Functions may return true or false values.

• True
• False

Answer 12

True

Question 12

When would you use a while loop?

Answer 12

Where you do not want the loop to iterate if the test condition is false from the beginning.

Ex: validating input that has been read and reading lists of data terminated by a sentinel value

Question 13

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

• True
• False

Answer 13

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

Question 14

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

• True
• False

Answer 14

True

Question 15

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

• True
• False

Answer 15

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

Question 16

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

Answer 16

Subscripts.

Question 17

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

Answer 17

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 18

This eliminates the need to place a function definition before all calls to the function.

Answer 18

Function prototype

aka

function declarations

Question 18

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

Answer 18

False

Question 18

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

Answer 18

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

Question 19

\_\_\_\_\_\_\_\_\_ _________ are passed to parameters automatically if no argument is provided in the function call. Where should they be assigned?

Answer 19

Default Arguments A function's default arguments should be assigned in the earliest occurrence of the function name. This will usually be the function prototype. If a function doesn't have a prototype, default arguments may be specified in the function header.

Question 20

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

Answer 20

* 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 21

A __________ __________ is a statement that causes a function to execute. A \_\_\_\_\_\_\_\_\_\_ __________ contains the statements that make up the function.

Answer 21

function call function definition

Question 22

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

Answer 22

True

Question 23

What operator allows you to access members of a structure?

Answer 23

The dot operator.

Question 24

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

Answer 24

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 25

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

Answer 25

* 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 26

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

Answer 26

False. A compiler error will result.

Question 27

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

Answer 27

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

Question 28

What does the vector function pop\_back do?

Answer 28

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

Question 29

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

Answer 29

False. You need to include namespace std.

Question 30

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

Answer 30

True

Question 31

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

Answer 31

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 33

When do you use the const keyword?

Answer 33

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

Question 34

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

Answer 34

The & (address) operator.

Question 35

When would you use a do-while loop?

Answer 35

Where you always want the loop to iterate at least once. Ex: good choice for repeating a menu or for asking user if they want to repeat a set of actions.

Question 37

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 37

True

Question 38

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

Answer 38

if (employee1.hours == employee2.hours)

Question 40

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 40

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 41

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

Answer 41

False, unless assigning an address during the declaration statement.

Question 42

Arrays are automatically passed by reference. * True * False

Answer 42

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 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

Constant pointers must be assigned an intial value when created. * True * False

Answer 45

True

Question 46

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

Answer 46

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

Question 47

What does the return statement do?

Answer 47

It causes a function to end immediately.

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 49

When a function uses a mixture of parameters with and without default arguments, the parameters with default arguments must be declared last. * True * False

Answer 49

True

Question 50

Array names are pointer constants. * True * False

Answer 50

True

Question 51

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

Answer 51

True

Question 52

What does the exit() function do?

Answer 52

Causes the a program to terminate, regardless of which function or control mechanism is executing.

Question 53

Pointer variables never store an address. * True * False

Answer 53

False

Question 54

A static local variable is destroyed when a function returns and exists for the entire life of the program. * True * False

Answer 54

False

Question 55

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

Answer 55

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

Question 57

When to should you use if(s)? When should you use if/else? When should you use if/else if? Trailing else?

Answer 57

* If both conditions could be true or both could be false, use two separate if statements. * If the two conditions are mutually exclusive, such that one must be true and the other false, and if/else should be used. * Use this chain of if statements to perform tests, one after the other, until one of them is found to be true. A trailing else provides a default action, when none of the if expressions are true

Question 58

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

Answer 58

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 59

You cannot have two local variables with the same name in the same function. * True * False

Answer 59

True

Question 60

What do the following vector member functions do? * vectorName.at(5) * vectorName.swap(vector2) * vectorName.reverse()

Answer 60

* vectorName.at(5) - Returns the value if the element at position 5 in the vector * vectorName.swap(vector2) - Swaps the contents of the vectorName with the contents of vector2 * vectorName.reverse() - Reverses the order of the elements in the vector (the last element becomes the first element, and the first element becomes the last element

Question 61

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 61

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 62

What are overloading functions?

Answer 62

Two or more functions may have the same name, as long as their parameter lists are different.

Question 64

What is a reference variable?

Answer 64

A reference variable references the memory location of another variable. Any change made to the reference variable is actually made to the one it references. Only variables can be passed by reference.

Question 65

A local variable is defined inside a function and can be accessible outside the function. * True * False

Answer 65

False it is not accessible outside the function.

Question 66

Pretest or Post-test? * While loop * do-while loop * For loop

Answer 66

* While loop -- pretest * do-while loop -- post-test * For loop -- pretest

Question 67

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 67

False. It must be passed to it by reference.

Question 68

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 68

True

Question 69

A program may be broken up into a set of manageable functions, or modules.

Answer 69

Modular programming.

Question 70

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 70

rates is a pointer to a constant double or rates points to a constant double .

Question 71

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 71

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

Question 72

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

Answer 72

True

Question 73

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

Answer 73

True

Question 74

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

Answer 74

You must compare their individual elements.

Question 75

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 75

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

Question 76

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

Answer 76

True

Question 77

In a union, all member variables occupy the same memory area and only one member can be used at a time. This is not the same for structures. * True * False

Answer 77

True

Question 78

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

Answer 78

True.

Question 79

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

Answer 79

* 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 80

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

Answer 80

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

Question 81

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

Answer 81

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

Question 82

What must be assigned to the pointer to a constant?

Answer 82

The address of a variable.