SYCS-135 Introduction to Programming

SYCS-135 Introduction to Programming - Fall 1999-2

Examination II - 100 points

Name: ___________ANSWER KEY_________________�� ID: _________________________

There are 36 questions on this exam.� The number of points N each question is worth in indicated by [N] at the beginning of the question narrative.

You should read each question carefully before answering.� If you must erase, do so completely.� The Exam is closed book.

�� _A__ 1.� [2] An example of a logical (Boolean) expression is an arithmetic expression followed by a relational �� operator followed by an arithmetic expression.

�� A)�� True

�� B)�� False

�� __A_ 2.� [2] This question is about short-circuit evaluation of logical expressions. Consider the following �� expression in some imaginary programming language (not C++):

��

�� (N > 5) AND (K / N < 12)

��

�� If N equals 0 when this expression is evaluated, which of the

�� following statements about the expression is true?

A)�� It causes a divide-by-zero error only if the language does not use short-circuit evaluation.

�� B)�� It causes a divide-by-zero error whether or not the language uses short-circuit evaluation.

�� C)�� It never causes a divide-by-zero error.

�� D)�� It causes a divide-by-zero error only if the language uses short-circuit evaluation.

�� _B__ 3.� [2] The expression� !(n < 5)� is equivalent to the expression� n > 5.

�� A)�� True

�� B)�� False

�� _A__ 4.� [2] Given the module description

��

�� PRINT AVERAGE (Level 1)

�� Print a heading

�� Print sumOfValues / countOfValues

��

�� the following is an appropriate module precondition:

�� "sumOfValues is assigned AND countOfValues does not

�� equal 0."

�� A)�� True

�� B)�� False

_A__ 5.� [2] The code segment

��

�� if (speed <= 40)

�� cout << "Too slow";

�� if (speed > 40 && speed <= 55)

�� cout << "Good speed";

�� if (speed > 55)

�� cout << "Too fast";

��

�� could be written equivalently as

��

�� if (speed <= 40)

�� cout << "Too slow";

�� else if (speed <= 55)

�� cout << "Good speed";

�� else

�� cout << "Too fast";

�� A)�� True

B) False

�� _E__ 6.�� [2] Which of the following is not a C++ relational operator?

�� A)�� <

�� B)�� !=

�� C)�� ==

�� D)�� >=

�� E)�� &&

_C__ 7.� [2] If p is a Boolean variable, which of the following logical expressions always has the value FALSE?

�� A)�� p && p

�� B)�� p || p

�� C)�� p && !p

�� D)�� p || !p

�� E)�� b and d above

�� _C__ 8.� [2] Which logical operator (op) is defined by the following table?

�� (T and F denote TRUE and FALSE.)

��

�� P� Q�� P op Q

�� ------------

�� T� T�� T

�� T� F�� F

�� F� T�� F

�� F� F�� F

�� A)�� OR

�� B)�� NOT

�� C)�� AND

�� D)�� none of the above

�� _E__ 9.�� [3] What is the output of the following C++ code fragment?

�� (Be careful here.)

��

�� int1 = 120;

�� cin >> int2;�� // Assume user types 30

�� if ((int1 > 100) && (int2 = 50))

�� int3 = int1 + int2;

�� else

�� int3 = int1 - int2;

�� cout << int1 << ' ' << int2 << ' ' << int3;

�� A)�� 120 30 150

�� B)�� 120 30 90

�� C)�� 120 50 70

�� D)�� 120 30 70

�� E)�� 120 50 170

�� _A__ 10.�� [3] What is the value of loopCount after control exits the following loop?

� �� loopCount = 1;

�� while (loopCount <= 145)

�� {

�� alpha = alpha + 7;

�� loopCount++;

�� }

�� A)�� 146

�� B)�� 1

�� C)�� 145

�� D)�� 144

�� _C__ 11.�� [3] After execution of the following code, what is the value of length?

�� (count and length are of type int.)

��

�� length = 5;

�� count = 4;

�� while (count <= 6)

�� {

�� if (length >= 100)

�� length = length - 2;

�� else

�� length = count * length;

�� count++;

�� }

��

�� A)�� 100

�� B)�� 600

�� C)�� 98

�� D)�� 20

E) none of the above

�� _E_ 12.�� [3] What is the output of the following code fragment? (finished is a Boolean variable, and firstInt �� and secondInt are of type int.)

��

�� finished = FALSE;

�� firstInt = 3;

�� secondInt = 20;

�� while (firstInt <= secondInt && !finished)

�� if (secondInt / firstInt <= 2)�� // Reminder: integer division

�� finished = TRUE;

�� else

�� firstInt++;

�� cout << firstInt << endl;

�� A)�� 5

�� B)�� 9

�� C)�� 8

�� D)�� 3

�� E)�� 7

�� 13.� [2] The condition that causes a loop to be exited is called the ___Termination Condition_____________.

�� 14.� [2] A(n) ____Sentinel________-controlled loop is an event-controlled loop whose event is the input of a special value.

�� 15.� [2] A(n) ___Flag______________-controlled loop is an event-controlled loop that uses a Boolean variable to record its event.

�� 16.� [2] A(n) ___Priming Read________ is an input statement located before the While loop that processes its input data.

�� _B_ 17.�� [2] When parameters are passed between the calling code and the called function, parameters and �� arguments are matched by:

�� A)�� their names

�� B)�� their relative positions in the parameter and argument lists

�� C)�� whether they are inputs to or outputs from the function

�� D)�� their data types

�� _E_ 18.�� [2] Parameter passage by reference is used if a parameter's data flow is

�� A)�� one-way, into the function.

�� B)�� one-way, out of the function.

�� C)�� two-way, into and out of the function.

�� D)�� a and b above

�� E)�� b and c above

�� _E_ 19.�� [2] Given the function prototype

��

�� void Fix( int&, float );

��

�� Which of the following is an appropriate function call? (someInt is of type int, and someFloat is of type float.)

�� A)�� Fix(24, 6.85);

�� B)�� someFloat = 0.3 * Fix(someInt, 6.85);

�� C)�� Fix(someInt + 5, someFloat);

�� D)�� a and c above

�� E)�� none of the above

�� _B_ 20.�� [3] Given the function definition

��

�� void Twist( 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 Twist?

�� (All variables are of type int.)

��

�� r = 1;

�� s = 2;

�� t = 3;

�� Twist(t, s);

�� cout << r << ' ' << s << ' ' << t << endl;

�� A)�� 5 14 3

�� B)�� 1 14 3

�� C)�� 1 14 9

�� D)�� 1 10 3

�� E)�� none of the above

�� _A_ 21.� [3] What is the output of the following code fragment? (All variables are of type int.)

��

�� alpha = 3;

�� beta = 20;

�� if (beta > 10)

�� {

�� int alpha = 5;

��

�� beta = beta + alpha;

�� cout << alpha << ' ' << beta << endl;

�� }

�� cout << alpha << ' ' << beta << endl;

�� A)�� 5 25

�� 3 25

�� B)�� 3 20

�� C)�� 5 25

�� 3 20

�� D)�� 5 25

�� 5 25

�� E)�� 3 25

�� 3 25

�� _D_ 22.� [2] In the following function, the declaration of beta includes an initialization.

��

�� void SomeFunc( int alpha )

�� {

�� int beta = 25;

�� ...

�� }

��

�� Which of the following statements about beta is false ?

�� A)�� It is initialized once only, the first time the function is called.

�� B)�� It is initialized each time the function is called.

�� C)�� It cannot be reassigned a different value within the function.

�� D)�� a and c above

�� E)�� b and c above

�� _E_ 23.�� [2] In the following function, the declaration of beta includes an initialization.

��

�� void SomeFunc( int alpha )

�� {

�� static int beta = 25;

�� ...

�� }

��

�� Which of the following statements about beta is false ?

�� A)�� It is initialized once only, the first time the function is called.

�� B)�� It is initialized each time the function is called.

�� C)�� It cannot be reassigned a different value within the function.

�� D)�� a and c above

�� E)�� b and c above

�� _C_ 24.�� [2] Given the function definition

��

�� bool IsZip( /* in */ float someFloat )

�� {

�� return (someFloat == 0.0);

�� }

��

�� what is the value of the expression� IsZip(2.4)� ?

�� A)�� true

�� B)�� 2.4

�� C)�� false

�� D)�� "someFloat == 0.0"

�� E)�� 0.0

�� 25.�� [2] Write the If statement for the following logic:� Only Sophmores (class_code = �S�) who have GPA�s between 2.5 and 3.5 will have their scholarship_amount increased by $500�

��

�� _______if (class_code == �S�) __________________________________________________

�� ____________if ((GPA > 2.5) && (GPA < 3.5)) ____________________________________

�� __________________scholarship_amount = scholarship_amount + 500;�� ___________

�� ___________________________________________________________________________.

�� _C_ 26.�� [2] The function heading

��

�� float TenToThePower( /* in */ int n )

��

is for a function that returns 10.0 raised to any integer power.Which of the following statements stores into someFloat the value 10.0 raised to the power someInt?

��

�� A)�� TenToThePower(someInt);

�� B)�� TenToThePower(someInt) = someFloat;

�� C)�� someFloat = TenToThePower(someInt);

�� D)�� someInt = TenToThePower(someFloat);

�� E)�� TenToThePower(someFloat, someInt);

27.� [2] The __Scope_______________ of an identifier is the region of program code where it is legal to reference that identifier.

28.� [2] The ___Lifetime______________ of a variable is the period of time during program execution when the variable has memory allocated to it.

_B_ 29.�� [2] If a module is supposed to print a line of asterisks of a given length, which is more appropriate to use--a value-returning function or a void function?

�� A)�� a value-returning function

�� B)�� a void function

_A_ 30.� [2] Any Switch statement that has a break statement after each case alternative can be replaced by a nested If-Then-Else structure.

�� A)�� True

�� B)�� False

_A_ 31.� [3] To produce the output� 2 4 6 8 10, what is the loop condition for the following loop?

��

�� n = 0;

�� do

�� {

�� n = n + 2;

�� cout << n << ' ';

�� } while ( ??? );

��

�� A)�� n < 10

�� B)�� n > 8

�� C)�� n <= 10

�� D)�� n < 8

�� E)�� n >= 2

�� _A_ 32.� [3] What is the output of the following code fragment if the input value is 'G'?

��

�� cin >> inputChar;

�� switch (inputChar)

�� {

�� case 'A' : cout << 1;

�� break;

�� case 'Q' : cout << 2;

�� break;

�� case 'G' :

�� case 'M' : cout << 3;

�� break;

�� default� : cout << 4;

��

�� A)�� 3

�� B)�� 4

�� C)�� There is no output.

�� D)�� 2

�� E)�� 1

33.� [2] In C++, the __Do-While_______________ statement is the looping control structure whose body is certain to execute at least once.

34.�� [8]� The following code segment contains logical errors that will yield erroneous results.� Write the correct code to the right of the given code that will write out all integers between 1000 and 0 inclusive that are divisible by 4, in descending order (i.e., 1000, 996, 992, ......., 8, 4, 0).

�� //INCORRECT CODE�� |�� //CORRECT CODE

�� |

�� int k = 1000;�� |�� int k = 1000;

�� while (k >= 0)�� |�� while ( k >= 0)

�� {�� |�� {

�� k = k - 4; �� |�� cout << k;

�� cout << k;�� |�� k = k � 4;

�� }�� |�� }

�� 35.�� [6] What is wrong with each of the following C=++ function definitions?

�� a.�� void Test1(int m, int n)

{

�� return 3 * n + m;

�� }

��

�� b.�� float Test2 (int i, float x)

�� {

�� i = i + 7;

�� x = 4.8 + float(i)

�� }��

�� a.______A value cannot be returned from this function�� __________________________

�� ___________________________________________________________________________

�� b. _____A value must be returned from this function�� _______________________________

�� ___________________________________________________________________________

36.� [12]� The following program adds two times together.� Both times are expressed in hours, minutes and seconds. First the program prompts the user to enter the current time. Then the program prompts the user to enter the amount of time they wish to add.� The program displays the result and terminates.

The function addtime adds the specified hours, minutes and seconds to the current time.� In this problem you must write the function body of addtime.�

You can assume that the input data is always correct.� The following is a sample of how the program should work:

�SAMPLE RUN: ��

�� Enter current time(hh mm ss): 12 55 45��

�� Enter clock adjustment (hh mm ss): 1� 10� 20��

�� Time reset to� 2: 6: 5��

________________________________________________________________________

#include <iostream.h>

void addtime (int&, int&, int&, int, int, int); �� //***** function prototype *****/

/***** main function *****/

int main ()

{

�� int current_hours, current_mins, current_secs;�� //current clock setting

�� int inhours, inmins, insecs;�� // hours, minutes & seconds needed to

�� // added to current time

�� while (cin)

�� {

�� cout << "\nEnter current time (hh mm ss): ";�� // prompt user to enter current time

�� cin >> current_hours >>current_mins >> current_secs; �� // get current time

�� cout << setw(2) << current_hours << ":"

�� << setw(2) << current_mins << current_secs << endl; // mirror the input

�� cout << "\nEnter clock adjustment (hh mm ss):"; �� // prompt user for time to add

�� cin >> inhours >> inmins >> insecs;�� // get time to be added

�� cout << setw(2) << inhours << ":" << setw(2) << inmins

�� << ":" << setw(2) << insecs <<endl;�� // mirror the input

�� addtime (current_hours, current_mins, current_secs, inhours, inmins, insecs);

�� // function call to the function you

�� // must write.� Remember that you

�� // should display the results as

�� // shown above in the sample run

�� }

�� return 0;

}

/***** USE THE VARIABLES SHOWN *****/

/***** IN THE FUNCTION HEADER BELOW *****/

void addtime(int& hours, �� // IN the current hours, OUT the total hours

�� int& minutes, �� // IN the current minutes, OUT the total minutes

�� int&, seconds�� // IN the current seconds, OUT the total seconds

�� int h, �� // IN: the hours to be added

�� int m, �� // IN: the minutes to be added

�� int s)�� // IN: the seconds to be added

/***** WRITE THE FUNCTION BODY HERE *****/

{

__seconds = seconds + s;____________________________________________________

__minutes = minutes + m;____________________________________________________

__if (seconds >= 60)________________________________________________________

__{_____________________________________________________________________

___�� seconds = seconds % 60;_________________________________________________

____minutes++;___________________________________________________________

__}____________________________________________________________________

__hours = hours + h;_______________________________________________________��

__if (minutes >= 60)________________________________________________________

__{______________________________________________________________________

___�� minutes = minutes % 60_______________________________________________

_______hours++;__________________________________________________________

�� }____________________________________________________________________

___if (hours > 12)__________________________________________________________

___{_____________________________________________________________________

____�� hours = hours � 12;____________________________________________________

___}_____________________________________________________________________

________________________________________________________________________

___cout << �time reset to << hours << �:� << minutes << �:� << seconds << endl;___________

________________________________________________________________________

}