Ch.5

Question 1

Given the following function declaration and local variable declarations, which of the following is not a correct function call?

int myInt;

float myFloat;

char ch;

void someFunction(int& first, float second, char third);

Answer 1

someFunction(1, 2.0, ch);

Question 2

What is the output of the following function and function call?

void calculateCost(int count, float& subTotal, float taxCost);

float tax = 0.0,

subtotal = 0.0;

calculateCost(15, subtotal,tax);

cout ≤≤ “The cost for 15 items is “ ≤≤ subtotal

≤≤ “, and the tax for “ ≤≤ subtotal ≤≤ “ is “ ≤≤ tax ≤≤ endl;

//end of fragment

void calculateCost(int count, float& subTotal, float taxCost)

{

if ( count ≤ 10)

{

subTotal = count * 0.50;

}

else

{

subTotal = count * 0.20;

}

taxCost = 0.1 * subTotal;

}

Answer 2

The cost for 15 items is 3.00, and the tax for 3.00 is 0.00;

Question 3

A simplified version of a function which is used to test the main program is called

Answer 3

a stub

Question 4

Testing your program should be done

Answer 4

as each function is developed.

Question 5

What is wrong with the following code?

int f1( int x, int y)

{

x = y * y;

return x;

int f2( float a, float& b)

{

if(a < b)

b = a;

else

a = b;

return 0.0;

}

}

Answer 5

Function definitions may not be nested.

Question 6

When a void function is called, it is known as

Answer 6

an executable statement.

Question 7

Given the function definition

void something ( int a, int& b )

{

int c;

c = a + 2;

a = a * 3;

b = c + a;

}

what is the output of the following code fragment that invokes something?

(All variables are of type int.)

r = 1;

s = 2;

t = 3;

something(t, s);

cout << r << ‘ ‘ << s << ‘ ‘ << t << endl;

Answer 7

1 14 3

Question 8

If you were to write a function for displaying the cost of an item to the screen, which function prototype would be most appropriate?

Answer 8

void display(float myCost);

Question 9

In the following function, what is passed to the first parameter?

void f1( int& value1, int value2);

int x,y;

f1(x,y);

Answer 9

the variable x (or its memory location)

Question 10

Which of the following are true?

A) As long as the function is defined anywhere in your program, it can be used anywhere else.

B) A function definition can contain another function definition.

C) A function can call another function.

D) If you have function prototypes, the order in which you define your functions is important.

Answer 10

A function can call another function.

Question 11

Given the following function definitions and program fragments, what is the output?

void f1(int& z, int &q)

{

int temp;

temp = q;

q = z;

z = temp;

}

void f2( int& a, int& b)

{

if( a < b)

f1(a,b);

else

a = b;

}

int x = 3, y = 4;

f2(y,x);

cout << x <<” “ << y << endl;

Answer 11

3 3

Question 12

A simplified main program used to test functions is called

Answer 12

a driver

Question 13

Call-by-reference parameters are passed

Answer 13

the actual argument.

Question 14

If you need a function to get both the number of items and the cost per item from a user, which would be a good function declaration to use?

Answer 14

void getData(int& count, float& cost);

Question 15

The postcondition of a function

Answer 15

tells what will be true after the function executes.

Question 16

What is the output of the following function and function call?

void calculateCost(int count, float& subTotal, float& taxCost);

float tax = 0.0,

subTotal = 0.0;

calculateCost(15, subTotal,tax);

cout << “The cost for 15 items is “ << subtotal

<< “, and the tax for “ << subTotal << “ is “ << tax << endl;

//end of fragment

void calculateCost(int count, float& subTotal, float& taxCost)

{

if ( count < 10)

{

subTotal = count * 0.50;

}

else

{

subTotal = count * 0.20;

}

taxCost = 0.1 * subTotal;

}

Answer 16

The cost for 15 items is 3.00, and the tax for 3.00 is 0.30;

Question 17

You should make a parameter a reference parameter if

Answer 17

you need the function to change the value of the argument passed to the function.

Question 18

What is the value of choice after the following statements?

void getChoice(int& par_choice, in par_count);

int choice, count = 3;

getChoice(choice, count);

void getChoice(int& par_choice, in par_count)

{

if(par_count < 0)

par_choice = 0;

if(par_count = 0)

par_choice = -1;

else

par_choice = 99;

return;

}

Answer 18

99

Question 19

If you write a function that should use call-by-reference, but forget to include the ampersand

Answer 19

the program will run with incorrect results

Question 20

Which of the following is true for a void function?

Answer 20

Nothing is returned

Question 21

Using functions in a program is called

Answer 21

Procedural Abstraction

Question 22

The values or variables listed in the function declaration are called ________ to the function

Answer 22

(formal) parameters

Question 23

When the address of the actual argument is passed to the formal parameter, this is called

Answer 23

call-by-reference –or- pass-by-reference

Question 24

A ________ is a main program that only checks that functions execute correctly

Answer 24

driver

Question 25

What type of value does a void function return?

Answer 25

nothing

Question 26

A function that does not return a value is known as a

Answer 26

void

Question 27

What symbol is used to signify that a parameter is a reference parameter?

Answer 27

ampersand (&)

Question 28

What is the correct way to call the following function?

void setDisplay( );

Answer 28

Set Display();

Question 29

A ________ is a simplified version of a function used to test the main program.

Answer 29

stub

Question 30

Pre and post conditions for a function should be written (before/after) the function definition is written

Answer 30

before

Question 31

It is acceptable to have both call-by-value and call-by-reference parameters in the same function declaration

Answer 31

True

Question 32

A void function may not be used in an output statement.

Answer 32

TRUE

Question 33

Functions can return at most one value.

Answer 33

TRUE

Question 34

In a function with call-by-reference parameters, the values of the actual arguments are passed to the function

Answer 34

FALSE

Question 35

It is illegal to call other functions from inside a function definition

Answer 35

FALSE