Deck 6: More Conditionals and Loops

Question 1

Each switch statement must terminate with a break statement.

Answer 1

False

Question 2

The following loop is syntactically valid:
for(int j = 0; j < 1000; j++) j--;

Answer 2

True

Question 3

A for statement is normally used when you do not know how many times the loop should be executed.

Answer 3

False

Question 4

A conditional operator is virtually the same as a switch statement.

Question 5

Given that s is a String, what does the following loop do? for(int j = s.length(); j > 0; j--)
System.out.print;

A) It prints s out backwards
B) It prints s out forwards
C) It prints s out backwards after skipping the last character
D) It prints s out backwards but does not print the first character
E) It yields a run-time error because there is no character at s.charAt(j-1) for j = 0

Question 6

A continue statement

A) may be used within a while or a do-while loop but not a for loop
B) is identical to a break statement within Java loops
C) may be used within any Java loop statement
D) may be used within a for loop but not within a while or a do-while loop
E) None of these

Question 7

A switch statement must have a default clause.

Question 8

If a switch statement contains no break statements at all,

A) a syntax error will occur
B) each of the case clauses will be executed every time the switch statement is encountered
C) this is equivalent to having the switch statement always take the default clause, if one is present
D) this is not a syntax error but nothing within the switch statement will ever be executed
E) None of these

Question 9

You might choose to use a switch statement instead of nested if-else statements if

A) the variable being tested might equal one of several hundred integer values
B) the variable being tested might equal one of a few integer values
C) there are two or more integer variables being tested, each one of which could be one of several hundred values
D) there are two or more integer variables being tested, each one of which could be one of a few values
E) None of these; you would never choose a switch statement instead of nested if-else statements under any circumstances.

Question 10

How many times will the following nested loop structure execute the innermost statement (x++;)? for(int j = 0; j < 100; j++)
For(int k = 100; k > 0; k--)
X++;

A) 100
B) 200
C) 10,000
D) 20,100
E) 1,000,000

Question 11

Given the following code, where x = 0, what is the resulting value of x after the for loop terminates? for(int i = 0; i < 5; i++)
X += i;

A) 0
B) 4
C) 5
D) 10
E) 15

Question 12

The do loop differs from the while loop in that

A) the while loop will always execute the body of the loop at least once
B) the do loop will always execute the body of the loop at least once
C) the do loop will continue to loop while the condition in its while statement is false and the while loop will continue to loop while the condition in its while statement is true
D) the while loop will continue to loop while the condition in its while statement is false and the do loop will continue to loop while the condition in its while statement is true
E) None of these; there is no difference between the two types of loops

Question 13

How many times will the following loop iterate? int x = 10;
Do {
System.out.println(x);
X--;
} while(x > 0);

A) 0 times
B) 1 time
C) 9 times
D) 10 times
E) 11 times

Question 14

The following for loop is an infinite loop::
for(int j = 0; j < 1000;) i++;

Question 15

Control in a switch statement jumps to the first matching case.

Question 16

In Java, it is possible to create an infinite loop out of while and do loops but not for loops.

Question 17

It is possible to convert any type of loop (while, do, for) into any other.

Question 18

How can the following statement be rewritten using a conditional operator? if(x <0) y = x;
Else y = 0;

A) y = (x < 0) ? x : 0;
B) x = (x < 0) ? y : 0;
C) (x < 0) ? y = x : y = 0;
D) y = (x < 0);
E) y = if(x < 0) x : 0;

Question 19

A loop can be used in a GUI to draw concentric circles.

Question 20

What does the break statement do?

A) It ends a program.
B) It transfers control out of the current control structure such as a loop or switch statement.
C) It ends the current line of output, returning the cursor.
D) It denotes the end of a switch statement.
E) It indicates the end of a line when using System.out.print.

Question 21

Which of the following statements are true about Java loops?

A) All three loop types are functionally equivalent.
B) while loops and do loops are essentially the same, but while loops always execute at least once.
C) If you know the number of times that a loop is to be performed, the best type of loop to use is a while loop.
D) Loops may be replaced by an appropriate combination of if-else and switch statements.
E) None of these

Question 22

Write code that outputs all of the int values between 1 and 100 with five values per line, and each of those five values spaced out equally. Use a single for loop to solve this problem.

Question 23

Rewrite the following nested if-else statements using an equivalent switch statement.
if (letter == 'A' || letter == 'a')
System.out.println("Excellent");
else if (letter == 'B' || letter == 'b')
System.out.println("You can do better");
else if (letter == 'C' || letter == 'c')
System.out.println("Try harder");
else if (letter == 'D' || letter == 'd')
System.out.println("Try much harder");
else System.out.println("Try another major! ");

Question 24

Write a declaration that initializes an int variable named num1 to 100 if the boolean variable score is true and to 50 otherwise, using the conditional operator.

Question 25

The following for loop is odd in that the loop increment value changes during iterations of the loop. Determine the number of times the loop iterates and the final value of j after the loop terminates.
int k = 0;
for (j = 0; j < 20; j += k)
k++;

Question 26

Rewrite the following if-else statement using a conditional operator.
if (x > y) z = x; else z = y;

Question 27

Write the code to display an ImageView named the_view at half its original size.

Question 28

Code Example Ch 06-1
In the following example, x is an int:
switch (x)
{
case 3 : x += 1;
case 4 : x += 2;
case 5 : x += 3;
case 6 : x++;
case 7 : x += 2;
case 8 : x--;
case 9 : x++
}
Refer to Code Example Ch 06-1: If x is equal to 3, what will the value of x be after the switch statement executes?

A) 5
B) 6
C) 11
D) 10
E) 12

Question 29

Which of the following would rotate an Ellipse named lipse 30 degrees counterclockwise?

A) lipse.setRotate(30);
B) lipse.setRotate(370);
C) lipse.setRotate(-30);
D) Ellipse.lipse.setRotate(30);
E) Ellipse.lipse.setRotate(-10*3);

Question 30

Write a do loop to obtain a list of scores from a teacher. The teacher should end input by entering the sentinel value, 999. The program should output the average of the scores.

Question 31

Given the following tax table information, write Java code to assign the double taxRate appropriately, given the double pay. Select the selection statement (if, if-else, switch) that makes the most sense.
If pay is more than 100,000, tax rate is 40%
If pay is more than 60,000 and less than or equal to 100,000, tax rate is 30%
If pay is more than 30,000 and less than or equal to 60,000, tax rate is 20%
If pay is more than 15,000 and less than or equal to 30,000, tax rate is 10%
If pay is more than 5,000 and less than or equal to 15,000, tax rate is 5%
If pay is less than or equal to 5,000, tax rate is 0%

Question 32

If a break occurs within the innermost loop of a nested loop that is three levels deep,

A) just the innermost loop will be "broken"
B) all loops are "broken" and execution continues from after the end of the loop
C) all but the outermost loops are "broken" and execution continues from the next iteration of the outermost loop
D) a syntax error is generated unless there are break or continue statements at each loop level
E) None of these are true

Question 33

How many times will the System.out.println("*"); statement execute inside of the following nested for loops? for(j = 0; j < 10; j++)
For(k = 10; k > j; k--)
System.out.println("*");

A) 50
B) 100
C) 55
D) 10
E) 20

Question 34

Describe a situation where you should use a do loop and a situation where you should use a while loop.

Question 35

Code Example Ch 06-1
In the following example, x is an int:
switch (x)
{
case 3 : x += 1;
case 4 : x += 2;
case 5 : x += 3;
case 6 : x++;
case 7 : x += 2;
case 8 : x--;
case 9 : x++
}
Refer to Code Example Ch 06-1: If x is equal to 5, what will the value of x be after the switch statement executes?

A) 8
B) 6
C) 11
D) 5
E) 10