Deck 2: Flow of Control

Question 1

Write multiway if-else statements for which the output is "Alarm: Boiler Pressure: TOO HIGH" if the value of the variable boiler_pressure is greater than 1000 (psi),and the output is "Boiler Pressure: TOO LOW" if the value of boiler_pressure is below 100(psi),otherwise the output is "Boiler Pressure: within normal limits."

Answer 1

if (boiler_pressure > 1000)
cout << "Boiler Pressure: TOO LOW\n";
else if (boiler_pressure < 100)
cout << "Boiler Pressure: TOO LOW\n";
else
cout << "Boiler Pressure: within normal limits.\n";

Question 2

In a do-while loop,a continue statement terminates the loop.

Answer 2

False

Question 3

In a while loop,the Boolean_Expression is executed before each execution of the loop body.

Answer 3

True

Question 4

Write Boolean expressions that represent the given English expressions.Assume any variables used have been declared and initialized.
a)alpha is greater than 1
b)x is odd
c)x and y are odd
d)ch is an upper case alphabetic character (between 'A' and 'Z').
e)digit,which is f type char,has value that is indeed a digit.

Question 5

A break statement is used in loops only.

Question 6

A numeric integer grade is between 50 and 99.Using integer division or otherwise obtain a int value that is 5,6,7,8,or 9 from the numeric grade.Write code using a switch statement using this number in the selector expression that assigns letter grades based on this 10 point scheme:
if the numeric_grade is not less than 90,the letter_grade is an A,
if the numeric_grade is not less than 80,the letter_grade is a B,
if the numeric_grade is not less than 70,the letter_grade is C,
if the numeric_grade is not less than 60,the letter_grade is D,
otherwise the letter_grade is F.

Question 7

The if,while and for statements control only one statement.

Question 8

Assume variables first,second,and max are declared to be double and are initialized.Write a sequence of lines of code that cause the larger of the values in first and second to be stored in max.

Question 9

Assume variables first and second are declared to be double and are initialized.Write a sequence of lines of code that cause the values stored in first and second to be exchanged if the value of first is not less than second.

Question 10

Write multiway if-else statements in which letter grades are assigned based a numeric grade based on this "ten point" scheme:
if the numeric grade is not less than 90,the letter grade is an A,
if the numeric grade is not less than 80,the letter grade is a B,
if the numeric grade is not less than 70,the letter grade is C,
if the numeric grade is not less than 60,the letter grade is D,
otherwise the letter grade is F.

Question 11

The value of count is 0;limit is 10.Evaluate:
(count == 0)&&(limit < 20)

Question 12

Suppose we have these declarations,
int x = -1,y = 0,z = 1;
This Boolean expression is correct and it does what the programmer intends.
x < y < z

Question 13

Given the declaration
int x = 0;
The following expression causes a divide by zero error:
(x !=0)|| (2/x < 1);

Question 14

Write Boolean expressions that represent the given English expressions.Assume any variables used have been declared and initialized.
a)at least one of x or y is odd
b)at least one of x or y is non-negative (x is non-negative is written x >= 0)
c)The hit is no more than 2.5 units away from target
d)x is 1 or x is equal to y
e)t is strictly between 3.2 and 3.3

Question 15

You want to determine whether time has run out.The following code correctly implements this.
!time > limit

Question 16

When a loop is nested in side another loop,a break or continue statement terminates or restarts the outermost loop of the nested loop structure.

Question 17

The value of count is 0;limit is 10.Evaluate:
count == 0 && limit < 20

Question 18

Use the condition operator (x?y:z)to write a very compact expression that assigns the maximum of variables n1 and n2 to the variable max.You should assume that any variables you use have been declared and initialized appropriately.

Question 19

Explain the programmer's saying from the text,section 2.2,"Garbage in means garbage out."

Question 20

The value of count is 0;limit is 10.Evaluate:
(count != 0)||(limit < 20)

Question 21

A switch statement must have

A)a default case
B)more than one non-default case
C)a break statement
D)none of the above
E)all of the above

Question 22

If the following code fragment is executed in an otherwise complete and correct program,which expression will be executed? Why? x = 0;
If (x = 12)
Yes_statement;
Else
No_statement;

A)The no_statement will be executed because x is not 12.
B)The statement has incorrect syntax so will not compile at all.
C)x=12 is illegal in the Boolean expression of an if statement.
D)The yes_statement will be executed.

Question 23

Write the following do-while statement with a while construct,and maybe some extra code.
x = 10;
do
{
cout << x << endl;
x = x - 3;
} while ( x > 0 );

Question 24

In the expression (j > 0 && j+1 == 10),which operator executes last?

A)>
B)&&
C)+
D)==

Question 25

For each of the following situations,tell which type loop (while,do-while,or for)would be best in that situation:
a)Reading a list of an unknown number of homework grades for a single student.
b)Summing a series such as 1 +1/2 +1/(22)+ 1/(23)+ … + 1/(28)
c)Testing a newly coded library function to see how it performs for different values of its arguments.
d)Reading in the number of days of vacation taken by an employee.

Question 26

Write a program that reads in and sums the squares of positive integers until a value that 0 or less is read in.

Question 27

Consider the if statement: if(condition)yes_clause;else no_clause;
Under which of the following circumstances will both the yes_clause and the no_clause will be executed?

A)When the condition is true.
B)When the condition is false.
C)When the condition is ambiguous.
D)This will not happen.

Question 28

Which of the following determines the operator that is processed prior to another operator?

A)Operator associativity
B)Operator precedence
C)Whether the operator is an arithmetic operator
D)None of these determine the order in which operators are processed.

Question 29

What is the output of the following,if it were embedded in an otherwise correct and complete program and run? int x = 10;
While (x > 0)
{
Cout << x << " ";
X = x + 3;
}
Cout << endl;

A)10 13 16 19 ...
B)The compiler detects that this will be an infinite loop,so it does not compile. Insert lowercase be
C)This is an infinite loop.When compiled and run,it runs until machine limitations stop it,or you get tired of it and kill the process.
D)0 3 6 9.

Question 30

Write a program that reads in exactly 10 integers and outputs the sum.

Question 31

Which of the following control structures requires curly braces?

A)if-else
B)while
C)do-while
D)switch
E)for

Question 32

Which of the following loop statements is guaranteed to iterate the body of the loop at least once?

A)while(control)body;
B)do body while(control);
C)for (initialize;test;update)body;
D)none of the above
E)all of the above

Question 33

Predict the output of the following nested loops:
int n = 1;
while(n <= 10)
{
int m = 10;
while(m>=1)
{
cout << n << " times " << m
<< " = " << n*m << endl;
m--;
}
n++;
}