Chapter 5

Answers to Exam Preparation Exercises

1. Evaluating Boolean expressions.

(a) T

(b) T

(c) T (AND has higher precedence than OR)

(d) F

3. Now

I'm

Adam

6. Output from code fragments:

(a) 10

10

(b) The value of X is 3

(c) 3

7

6

5. What is written from nested IFs.

(a) Eligible to serve.

(b) Too short and too light to serve.

7. Rewriting expressions in Pascal.

(a) (X < Y) AND (Y <= Z)

(b) (X > 0) AND (Y > 0) AND ( Z > 0)

(c) (X <> Y) AND (X <> Z)

(d) (X = Y) AND (X = Z)

8. Evaluating Boolean expressions

(a) T

(b) F

(c) F

(d) T

(e) T

11. Inserting a BEGIN-END pair.

IF TypeA OR TypeB

THEN

BEGIN

IF TypeA AND TypeB

THEN

Writeln('Type AB')

END

ELSE

Writeln('Type O');

12. Data sets that test each of five branches.

A B C Expected Output

Set 1 'A' 'A' 'A' All initials are the same.

Set 2 'A' 'A' 'B' First two are the same.

Set 3 'B' 'A' 'A' Last two are the same.

Set 4 'A' 'B' 'A' First and last are the same.

Set 5 'A' 'B' 'C' All initials are different.

Answers to Programming Warm-Up Exercises

2. Declaration and assignment for a Boolean variable.

VAR

Eligible:

Boolean;

Eligible := True

3. Candidate := (SATScore >= 1100) AND (GPA >= 2.5) AND (Age > 15);

5. Biggest of three variables I, J, and K, using IF-THEN statements:

Biggest := K;

IF J > Biggest

THEN

Biggest := J;

IF I > Biggest

THEN

Biggest := I;

using IF-THEN-ELSE statements:

IF I > J

THEN

IF I > K

THEN

Biggest := I

ELSE

Biggest := K

ELSE

IF J > K

THEN

Biggest := J

ELSE

Biggest := K;

8. Correcting syntax errors.

PROGRAM Exercise (Input, Output);

CONST

A = 10;

VAR

D,

E,

F:

Integer;

BEGIN

Read(D, E, F);

IF (D > A)

THEN

D := A + D

ELSE

D := A;

E := D + F;

Write('This program does not make sense', E, F, D)

END.

10. Program segment for slope of a line:

IF X1 = X2

THEN

Writeln('Slope undefined')

ELSE

BEGIN

M := (Y1 - Y2)/(X1 - X2);

Writeln('The slope is ',M)

END

11. Quadratic formula code segment:

Discriminant := B * B - 4 * A * C;

IF Discriminant < 0

THEN

Writeln('No real roots.')

ELSE

BEGIN

Root1 := (-B + Discriminant)/(2 * A);

Root2 := (-B - Discriminant)/(2 * A)

END

12. Smallest of three variables A, B, and C, using nested IF statements:

IF A < B

THEN

IF A < C

THEN

SmallestInteger := A

ELSE

SmallestInteger := C

ELSE

IF B < C

THEN

SmallestInteger := B

ELSE

SmallestInteger := C;