Deck 6: Loops

Question 1

What is the output of the code snippet given below?

A)no output
B)abcd
C)abcde
D)bcde

Answer 1

bcde

Question 2

How many times does the code snippet given below display "Loop Execution"?

A)infinite times
B)8 times
C)9 times
D)10 times

Answer 2

9 times

Question 3

How many times will the following loop run?

A)0
B)8
C)9
D)10

Answer 3

10

Question 4

What is the output of the following code snippet?

A) 1 3 5 7 9 11 13 15 17 19
B) 1 3 5 7 9 11 13 19
C) 1 3 5 7 9 11 13 15 17
D) 1 3 5 7 9 11 13 17 19

Question 5

What is the output of the code fragment given below?

A)0
B)62
C)63
D)The code fragment displays no output because it does not compile.

Question 6

What is the output of the code snippet given below?

A)no output
B)0 2 4 6 8
C)10 12 14 16 18 ….(infinite loop)
D)0 2 4 6 8 10 12 14 ….(infinite loop)

Question 7

What is the output of the following code snippet?

A)No output because of compilation error.
B)"Inside the while loop" will be displayed 10 times.
C)No output after successful compilation.
D)"Inside the while loop" will be displayed only once.

Question 8

Which error type does the "off-by-one" error belong to?

A)syntax error
B)compile-time error
C)run-time error
D)infinite loop

Question 9

What is the output of the code snippet given below?

A)no output
B)13
C)24
D)2345

Question 10

What is the output of the following code snippet?

A)1 3 5
B)1 3 9
C)1 3 5 7 9
D)1 3 5 9

Question 11

What are the values of i and j after the following code fragment runs?

A)i = 1951, j = 0
B)i = 1951, j = 45
C)i = 65, j = 1
D)i = 65, j = 45

Question 12

What output does this while loop generate?

A)No output is generated.
B)6, 5, 4, 3, 2, 1
C)6, 5, 4, 3, 2, 1,
D)The output is infinite.

Question 13

What is the output of the following code snippet?

A)r = 16.0
B)r = 128.0
C)r = 4096.0
D)r = 65536.0

Question 14

What are the values of i and j after the following code snippet is run?

A)
B)
C)
D)

Question 15

How many times does the code snippet below display "Hello"?

A)infinite times
B)14 times
C)15 times
D)16 times

Question 16

What is the output of the following code fragment?

A) The value of sum is 0 .
B) The value of sum is 9 .
C) The value of sum is 12 .
D) The value of sum is 21 .

Question 17

What is the output of the following code fragment?

A)The value of sum is 65.
B)The value of sum is 66.
C)The value of sum is 55.
D)The value of sum is 56.

Question 18

The code snippet below checks whether a given number is a prime number.What will be the result of executing it?

A)The code snippet will not compile.
B)The code snippet will display the desired result.
C)The code snippet will display an incorrect result if the number is 1.
D)The code snippet will loop forever.

Question 19

How many times does the following code fragment display "Hi"?

A)9 times
B)10 times
C)11 times
D)12 times

Question 20

What is the output of the code fragment given below?

A)j=27
B)j=12
C)j=13
D)j=14

Question 21

When hand-tracing a portion of code, which statement about Boolean conditions is true?

A)They typically are too complex to be evaluated.
B)They do not need to be monitored because their result usually is not stored in a variable.
C)It is rare to encounter a Boolean condition.
D)They are crucial to evaluate since they determine if-statement conditions and looping control.

Question 22

Which of the following statements is true about the variable sum in the code snippet below?

A)It contains the value 10 after the loop is finished executing.
B)It contains the value 11 after the loop is finished executing.
C)It is the cause of an infinite loop.
D)It disappears after the loop is done executing.

Question 23

What is the best strategy for avoiding off-by-one errors?

A)Randomly insert +1 or -1 until the program seems to work.
B)Think through a couple of test cases and use the results to come up with a rationale for decisions.
C)Always start a loop at 0.
D)Never use the < operator by itself in a comparison test.

Question 24

What is the output of the following code snippet?

A) 0 1 5 7 9 11 13 15 17 19
B) 0 1 1 2 3 5 8 13 21 34 55
C) 0 1 4 6 8 10 12 14 16 18
D) 0 1 6 7 9 12 14 17 19 21

Question 25

Which of the following code snippets displays the output exactly 10 times?

A) int i=0;
while (i<10);
{
System. out.println("This is example 1.");
i++;
}
B) int i = 0 ;
while (i < 10)
{ System.out.println("This is example 2.");
i++;
}
C) Int i=0;
while (i<10)
{
System. out.println("This is example 3.");
}
D) int i=1;
while (i<10)
{
System. out.println("This is example 4.");
i++;
}

Question 26

What changes do you need to make in the following code snippet to display "Let us learn Java" exactly 10 times?

A)while (i < 9)
B)while (i < 11)
C)while (i < 12)
D)int i = 1;

Question 27

What is the output of the following code snippet?

A) 1 End
B) 1 End (but the loop is an infinite loop)
C) 1 2 3 4 5 6 7 8 End
D) 1 2 3 4 5 6 7 8 End (but the loop is an infinite loop)

Question 28

What values does counter variable i take on when this loop executes?

A)20, 14, 8, 2
B)20, 14, 8, 2, -4
C)20, 14, 8
D)14, 8, 2

Question 29

What for loop can be used in the indicated area so the code will print:

A)for (int num = 0; num < 4 - val; num++)
B)for (int num = 0; num < val; num++)
C)for (int num = 4; num < val; num++)
D)for (int num = 4; num > 0; num--)

Question 30

What is the output of this code snippet?

A)3 4 5
B)3
C)3 3 3 3 3 ...(infinite loop)
D)0 1 2

Question 31

When hand tracing, drawing a line through the value stored in a variable means that the

A)value stored there has changed to something new.
B)variable is the wrong data type for the code being executed.
C)expression being evaluated uses that variable.
D)variable must be inside a loop.

Question 32

The process of hand-tracing code is valuable because

A)it is usually faster than just running the code.
B)it is the best way to design an algorithm.
C)you must already have a working program in order to do it.
D)it gives valuable insight that you do not get by running the code.

Question 33

This code snippet is intended to calculate the balance of an account after twenty years of gaining interest.Select the statement that correctly completes the loop.

A)years++;
B)years--;
C)balance++;
D)balance--;

Question 34

Assuming the variable n is an integer that stores a positive value, which of the following is a loop with a bound that could be problematic?

A)for (i = 1; i != n; i++)
B)for (years = n; years < 0; years--)
C)for (i = 1; i <= n; i++)
D)for (int i = 1; i <= 10; i++)

Question 35

How many times does the loop execute in the following code fragment?

A)11
B)12
C)13
D)14

Question 36

What is the output of the code snippet given below?

A)No output
B)0 3 6 9 12 15 18
C)0 1 3 5 7 9
D)0 3 6 9 ….(infinite loop)

Question 37

When hand-tracing the loop in the code snippet below, which variables are important to evaluate?

A)the variables i and j only
B)the variables i and sum
C)the variables i, j, and k
D)Tthe variables j and k only

Question 38

What will be the result of running the following code fragment?

A)The code fragment will display the interest calculated for nine years.
B)The code fragment will continue to display the calculated interest forever because the loop will never end.
C)The code fragment will not display the calculated interest and halt abruptly.
D)The code fragment will not display any output because it will not compile.

Question 39

Which of the statements about hand-tracing is true?

A)You need a working program in order to do hand-tracing.
B)Hand-tracing can be done with pseudocode.
C)Hand-tracing will clearly show how long a program will take to execute.
D)The goal of hand-tracing is to double check the answers of the running code.

Question 40

How many times does the following code snippet display "Loop Execution"?

A)ten times
B)The code snippet does not run because of a compile error.
C)infinite loop
D)only one time

Question 41

What is the output of the following loop?

A)37
B)36
C)25
D)24

Question 42

What is the output of the following code?

A)1
B)2
C)3
D)4

Question 43

Which loop does not check a condition at the beginning of the loop?
I.the do loop
II.the while loop
III.the for loop

A)I and II
B)I and III
C)I only
D)III only

Question 44

Which of the following statements expresses why the following code is considered bad form?
for (rate = 5; years-- > 0; System.out.println(balance))
...
I.unrelated expressions in loop header
II.doesn't match expected for loop idiom
III.loop iteration is not clear

A)II and III only
B)I and II only
C)I and III only
D)I, II, and III

Question 45

Which of the following loops executes the statements inside the loop before checking the condition?

A)for
B)while
C)do
D)do-for

Question 46

Which statement about this code snippet is accurate?

A)The loop will run 50 times.
B)The loop will never stop.
C)The loop will run at most 50 times, but may stop earlier when balance exceeds or equals targetBalance.
D)There is a compilation error.

Question 47

What is the output of the code snippet given below?

A)abcd
B)bcde
C)bcbcd
D)cdef

Question 48

What is the output of the following code snippet?

A)100
B)49.50
C)60.5
D)10

Question 49

Given the following code snippet, what should we change to have 26 alphabet characters in the string str?

A)int c = 'A'
B)str = c + str;
C)c <= 'Z'
D)must change to use a do loop

Question 50

What is the output of the code snippet given below?

A)no output
B)no output (infinite loop)
C)abcde
D)bcde

Question 51

Is the code snippet written below legal? (lines are numbered for reference)

A)Yes.
B)No; there should be a semicolon at the end of line 2.
C)No; for i = 4, s.substring(i, i + 1) will result in an StringIndexOutOfBounds error.
D)No; line 4 should have no semicolon at the end.

Question 52

The for loop header can contain multiple variables of the same type and multiple update expressions, separated by commas:

for (int i = 0; j = 3; i <= 5; i++, j--)
Which loop below correctly implements the same loop using a single counter in the loop control?

A) int i=0;
for (int j=3 ; j<=5 ; j++ )
{
i++;
}
B) Int i=3;
for (int j=0 ; j<=5 ; j++ )
{
i++;
}
C) int j=3;
for (int i=0 ; i<=5 ; j--)
{
i++;
}
D) Int j=3;
for (int i=0 ; i<=5 ; i++)
{
. . .
j--;
}

Question 53

In the __________ loop header, you can include multiple update expressions, separated by commas, but it is not recommended.

A)do
B)while
C)for
D)if

Question 54

What is the output of the code snippet given below?

A)no output
B)no output (infinite loop)
C)12345
D)2345

Question 55

Which of the following for loops is illegal?

A)for (int i = 0; ; ) { }
B)for (int i = 0) { }
C)for (int i = 0, k = 1; ; i++) { }
D)for ( ; ; )

Question 56

How many times does the following loop execute?

A)10
B)9
C)8
D)an infinite number of times

Question 57

What does the following code snippet print?

A)10
B)20
C)30
D)40

Question 58

How many times does the following loop run?

A)0 times
B)1 times
C)2 times
D)4 times

Question 59

Which of the following loops executes 8 times?

A)for (years = 8; years >= 0; years--)
B)for(i = 0; i <= 7; i++)
C)for(i = 1; i <= 10; i++)
D)for (int i = 19; i >= 11; i--)

Question 60

Consider the following loop:
int n=1;
double x=0;
double s;
do
{
s=1.0 /(n * n) ;
x=x+5 ;
n++;
}
while (s>0.01);
System. out. println(x);
Which loop below is an equivalent loop?

A) double x=0;
double s=1;
for (int k=1 ; s>0.01 ; k++ )
{
s=1.0 /(k * k) ;
x=x+s ;
}
System. out. println(x);
B) double x=0;
double s=1;
for (int k=1 ; k<100 ; k++ )
{
s=1.0 /(k * k) ;
x=x+5;
}
System. out.println(x);
C) double x=0;
double s=1;
int k=10;
while (s>0.01)
{
s=1.0 /(k * k) ;
x=x+s ;
k++;
}
System.out. println(x);
D) double x=0;
double s=10;
int k=1;
while (s>0.01)
{
s=1.0 /(k * k) ;
x=x+s;
k++;
}
System.out. println(x);

Question 61

Is the following code snippet legal?

A)Yes, it is legal but does not print anything.
B)Yes, it is legal and prints "Do you think in Java?" once.
C)Yes, it is legal and prints "Do you think in Java?" twice.
D)No, it is not legal and gives a compilation error.

Question 62

Which of the following statements is correct about a sentinel?

A)A sentinel is a value that creates a bridge between a data set and unrelated input.
B)A sentinel is a value that is part of the data to be processed by the program.
C)A sentinel is a value that terminates a program.
D)A sentinel is a value that indicates the end of an input sequence.

Question 63

What does the following code snippet display?

A)It displays random Unicode characters.
B)It displays random ASCII characters.
C)Nothing because it has compilation error.
D)It displays the hexadecimal characters between '0' and 'F.'

Question 64

Which of the loop(s) test the condition after the loop body executes?
I.the for loop
II.the while loop
III.the do loop

A)I only
B)II only
C)III only
D)II and III

Question 65

What will be the output of the following code snippet?

A)Hello will be displayed infinitely many times.
B)There will be no output as the code snippet will not compile.
C)There will be no output after successful compilation.
D)Hello will be displayed only once.

Question 66

How do you fix this code snippet to make it print out the sum when the user enters a letter rather than a double? The user must enter at least one double when the program begins.

A)while (in.hasData());
B)while (!in.hasEnded());
C)while (in.hasNextDouble());
D)while (hasData);

Question 67

Which of the following loop(s) could possibly not enter the loop body at all?
I.the for loop
II.the while loop
III.the do loop

A)I only
B)I and II only
C)II and III only
D)I and III only

Question 68

Which of the following loops executes exactly 10 times?

A) for (int i=0 ; i<=10 ; i++ ) { }
B) Int i=0;
boolean found = false;
do
{
i++;
if ( i% 10==0)
{
found = true;
}
}
while ( i<10 && ! found);
C) int i = 0;
while (i <=10)
{
i++;
}
D) for (int i=1 ; i<=10 ; i++ )

Question 69

Which statement, inserted at the indicated blank line, will correctly terminate this loop when the end of input is reached (detected when the user enters the letter Q)?

A)stop;
B)done = 1;
C)exit;
D)done = true;

Question 70

How many times does the following loop execute?

A)1 time
B)2 times
C)3 times
D)4 times

Question 71

Which of the following should be used when you need to ask a user to enter one data item and repeat the prompt if the data is invalid?
I.the for loop
II.the while loop
III.the do loop

A)I only
B)I and II
C)III only
D)II only

Question 72

Suppose that a program asks a user to enter multiple integers, either positive or negative, to do some calculation.The data entry will stop when the user enters a certain value to indicate the end of the data.What value should the program use as the sentinel?

A)0
B)-1
C)999
D)an alphabetic character

Question 73

What is the output of the code snippet given below?

A)a
B)ae
C)aeiou
D)aei

Question 74

What will be the output of the following code snippet?

A)Hello will be displayed infinitely many times.
B)There will be no output as the code snippet will not compile.
C)There will be no output after successful compilation.
D)Hello will be displayed only once.

Question 75

What is the sentinel value in the following code snippet?

A)0
B)1
C)2
D)-1

Question 76

Which statement is correct about the execution of the loop in the following code fragment?

A)The loop will execute only when 0 is entered.
B)The execution of the loop is independent of user input.
C)The program prints the count of positive inputs.
D)The loop will execute at least once even if the user has entered the sentinel value.

Question 77

What is the outcome of the following code snippet?

A)No output will be displayed because of a compilation error.
B)Hello will be displayed only once.
C)Hello will be displayed infinite times.
D)No output will be displayed even after successful compilation of the code snippet.

Question 78

What is the output of this code snippet?

A) 2 4 7 11 16 22
B) 1 3 5 7 9
C) 2 3 5 6 7
D) 2 4 6 8

Question 79

How many times is the text "Let's have fun with Java." printed when this code snippet is run?

A)1
B)2
C)3
D)10

Question 80

What will be the final output of the following code snippet when a user enters input values in the order 10, 20, 30, 40, 50, and -1?

A)The Average Salary: 0.0
B)The Average Salary: 30.0
C)No data!
D)There will be no output as the code snippet will not compile.