Question 1

Which of the following loops executes exactly 10 times?

Accepted Answer

Loop D uses a for loop with a clear start (1) and end (10) point, so it will execute exactly 10 times.

Question 2

What are the values of i and j after the following code snippet is run?
Int i = 10;
Int j = 20;
Int count = 0;
While (count < 5)
{
I = i + i;
I = i + 1;
J = j - 1;
J = j - j;
Count++;
}
System.out.println("i = " + i + ", j = " + j);

Accepted Answer

The answer of What are the values of i and...

Question 3

What is the output of this loop?
int i = 0;
boolean found;
while (i < 20 && !found)
{
int sum = i * 2 + i * 3;
System.out.print(sum + " ");
if (sum > 50)
{
found = true;
}
i++;
}

Accepted Answer

The answer of What is the output of this loop?
int...

Question 4

What is the last output line of the code snippet given below?
Int i = 0;
While (i < 10)
{
Int num = 1;
For (int j = i; j > 1; j--)
{
System.out.print(j + " ");
Num = num * 2;
}
System.out.println("***");
I++;
}

Accepted Answer

The answer of What is the last output line of...

Question 5

What is the output of the following code snippet?
Double a = 2;
Int n = 16;
Double r = 1;
Double b = a;
Int i = n;
While (i > 0)
{
If (i % 2 == 0) // n is even
{
B = b * b;
I = i / 2;
}
Else
{
R = r * b;
I--;
}
}
System.out.println("r = " + r);

Accepted Answer

The answer of What is the output of the following...

Question 6

What is the output of the code snippet given below?
String s = "abcdefghijkl";
Int i = 1;
Do
{
If (i > 2)
{
System.out.print(s.substring (1, i));
}
I++;
}
While (i < 5);

Accepted Answer

The answer of What is the output of the code...

Question 7

What is the output of the following code fragment?
Int i = 1;
Int sum = 0;
While (i <= 15)
{
Sum = sum + i;
I++;
}
System.out.println("The value of sum is " + sum);

Accepted Answer

The code fragment initializes the variable i to 1 and the variable sum to 0. The while loop iterates as long as i is less than or equal to 15. During each iteration, the current value of i is added to the variable sum, and then i is incremented by 1. Therefore, the loop adds up the values of 1, 2, 3, ..., 15, resulting in a final value of sum equal to 120. This value is printed out using System.out.println(). Therefore, the output is "The value of sum is 120" (option C).

Question 8

What does the following code snippet display?
Char ch1 = '\ u0000';
Char ch2 = '\ uffff';
For (int i = 0; i < 1000; i++)
{
If (i % 50 == 0)
{
System.out.println();
}
System.out.print((char)(ch1 + Math.random() * (ch2 - ch1 + 1)));
}

Accepted Answer

The code snippet generates and prints random Unicode characters between the characters represented by ch1 (which is the null character) and ch2 (which is the last Unicode character). Hence, option A is correct.

Question 9

What does the following code do?
Int sum = 0;
Final int count = 1000;
For (int i = 1; i <= count; i++)
{
Sum = sum + (int) (Math.random() * 101);
}
System.out.println(sum / count);

Accepted Answer

The code initializes a variable "sum" to 0 and a final variable "count" to 1000. Then it enters a loop and generates a random integer between 0 and 100 (inclusive) in each iteration, adds it to the sum variable. Finally, it calculates and prints the average of the 1000 generated random integers by dividing the sum by count. Therefore, the code calculates the average of 1000 random numbers between 0 and 100.

Question 10

Which of the following for loops is illegal?

Accepted Answer

Option B is illegal because it lacks the third expression which is used to update and control of the loop. It should be updated like this:

for (int i = 0; i < n; i++) { }  #where n is the number of iterations.

Question 11

How many times does the following loop execute?
double d;
double x = Math.random() * 100;
do
{
d = Math.sqrt(x) * Math.sqrt(x) - x;
System.out.println(d);
x = Math.random() * 10001;
}
while (d != 0);

Accepted Answer

The loop executes at least once due to the do-while structure, but it's impossible to determine how many times it will execute because it depends on the random value of `x` leading to `d` being exactly 0, which is unlikely but not impossible.

Question 12

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

Accepted Answer

The answer of In the __________ loop header, you can...

Question 13

What is the output of the following code snippet?
Int counter = 1;
For (double i = 0.01; i <= 1.0; i = i + 0.01)
{
Counter++;
}
System.out.println(counter);

Accepted Answer

The loop runs 100 times (from 0.01 to 1.0 in increments of 0.01), and the counter is incremented each time. Therefore, the output is 100.

Question 14

Choose the loop that is equivalent to this loop.
Int n = 1;
Double x = 0;
Double s;
Do
{
S = 1.0 / (n * n);
X = x + s;
N++;
}
While (s > 0.01);

Accepted Answer

The for loop in choice A has the same logic and condition as the while loop in the original code. It also initializes s to 1 and uses a variable k to increment the value of s in each iteration.

Question 15

Insert a statement that will correctly terminate this loop when the end of input is reached.
Boolean done = false;
While (!done)
{
String input = in.next();
If (input.equalsIgnoreCase("Q"))
{
__________
}
Else
{
Double x = Double.parseDouble(input);
Data.add(x);
}
}

Accepted Answer

The best choice to terminate the loop when the end of input is reached is to set the "done" variable to true using the statement "done = true". This will cause the condition of the while loop to evaluate to false and therefore terminate the loop. Option A ("stop") and option C ("exit") are not valid Java statements, while option B ("done = 1") is syntactically valid but assigns an integer value to a boolean variable which is not allowed.

Question 16

What is the output of the following code snippet?
Int f1 = 0;
Int f2 = 1;
Int fRes;
System.out.print(f1 + " ");
System.out.print(f2 + " ");
For (int i = 1; i < 10; i++)
{
FRes = f1 + f2;
System.out.print(fRes + " ");
F1 = f2;
F2 = fRes;
}
System.out.println();

Accepted Answer

The code implements the fibonacci sequence, where each number is the sum of the two preceding ones, starting from 0 and 1. The output will be the first 10 numbers in the sequence: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34. Therefore, the correct answer is choice B.

Question 17

What values does counter variable i assume when this loop executes?
For (int i = 20; i >= 2; i = i - 6)
{
System.out.print(i + ",");
}

Accepted Answer

The answer of What values does counter variable i assume...

Question 18

What is the output of this code snippet if the user enters the numbers 1 2 3 4 -1 5?
Double total = 0;
Boolean hasValidNumber = true;
Scanner in = new Scanner(System.in);
While (in.hasNextDouble() && hasValidNumber)
{
Double input = in.nextDouble();
If (input < 0)
{
HasValidNumber = false;
}
Else
{
Total = total + input;
}
}
System.out.println(total);

Accepted Answer

The answer of What is the output of this code...

Question 19

What does the following code snippet print?
int a = 120;
int b = 90;
int n1 = Math.abs(a);
int n2 = Math.abs(b);
int result = 1;
for (int k = 1; k <= n1 && k <= n2; k++)
{
if (n1 % k == 0 && n2 % k == 0)
{
result = k;
}
}
System.out.println(result);

Accepted Answer

The program calculates the greatest common divisor (GCD) of the two numbers `a` and `b`. It does this by finding all the factors of both `n1` and `n2` and then selecting the largest one that is a factor of both.
In this case, n1 is 120 and n2 is 90. The factors of 120 are 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 20, 24, 30, 40, 60, and 120. The factors of 90 are 1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, and 90. The largest factor that is common to both is 30, so that is the value of `result` that will be printed.

Question 20

Which of the following is considered a loop with a bound that could be problematic?

Accepted Answer

The answer of Which of the following is considered a...

Quiz 4: Loops

Which of the following loops executes exactly 10 times?

What are the values of i and j after the following code snippet is run? Int i = 10; Int j = 20; Int count = 0; While (count < 5) { I = i + i; I = i + 1; J = j - 1; J = j - j; Count++; } System.out.println("i = " + i + ", j = " + j) ;

What is the output of this loop? int i = 0; boolean found; while (i < 20 && !found) { int sum = i * 2 + i * 3; System.out.print(sum + " ") ; if (sum > 50) { found = true; } i++; }

What is the last output line of the code snippet given below? Int i = 0; While (i < 10) { Int num = 1; For (int j = i; j > 1; j--) { System.out.print(j + " ") ; Num = num * 2; } System.out.println("***") ; I++; }

What is the output of the following code snippet? Double a = 2; Int n = 16; Double r = 1; Double b = a; Int i = n; While (i > 0) { If (i % 2 == 0) // n is even { B = b * b; I = i / 2; } Else { R = r * b; I--; } } System.out.println("r = " + r) ;

What is the output of the code snippet given below? String s = "abcdefghijkl"; Int i = 1; Do { If (i > 2) { System.out.print(s.substring (1, i) ) ; } I++; } While (i < 5) ;

What is the output of the following code fragment? Int i = 1; Int sum = 0; While (i <= 15) { Sum = sum + i; I++; } System.out.println("The value of sum is " + sum) ;

What does the following code snippet display? Char ch1 = '\ u0000'; Char ch2 = '\ uffff'; For (int i = 0; i < 1000; i++) { If (i % 50 == 0) { System.out.println() ; } System.out.print((char) (ch1 + Math.random() * (ch2 - ch1 + 1) ) ) ; }

What does the following code do? Int sum = 0; Final int count = 1000; For (int i = 1; i <= count; i++) { Sum = sum + (int) (Math.random() * 101) ; } System.out.println(sum / count) ;

Which of the following for loops is illegal?

How many times does the following loop execute? double d; double x = Math.random() * 100; do { d = Math.sqrt(x) * Math.sqrt(x) - x; System.out.println(d) ; x = Math.random() * 10001; } while (d != 0) ;

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

What is the output of the following code snippet? Int counter = 1; For (double i = 0.01; i <= 1.0; i = i + 0.01) { Counter++; } System.out.println(counter) ;

Choose the loop that is equivalent to this loop. Int n = 1; Double x = 0; Double s; Do { S = 1.0 / (n * n) ; X = x + s; N++; } While (s > 0.01) ;

Insert a statement that will correctly terminate this loop when the end of input is reached. Boolean done = false; While (!done) { String input = in.next() ; If (input.equalsIgnoreCase("Q") ) { __________ } Else { Double x = Double.parseDouble(input) ; Data.add(x) ; } }

What is the output of the following code snippet? Int f1 = 0; Int f2 = 1; Int fRes; System.out.print(f1 + " ") ; System.out.print(f2 + " ") ; For (int i = 1; i < 10; i++) { FRes = f1 + f2; System.out.print(fRes + " ") ; F1 = f2; F2 = fRes; } System.out.println() ;

What values does counter variable i assume when this loop executes? For (int i = 20; i >= 2; i = i - 6) { System.out.print(i + ",") ; }

What does the following code snippet print? int a = 120; int b = 90; int n1 = Math.abs(a) ; int n2 = Math.abs(b) ; int result = 1; for (int k = 1; k <= n1 && k <= n2; k++) { if (n1 % k == 0 && n2 % k == 0) { result = k; } } System.out.println(result) ;

Which of the following is considered a loop with a bound that could be problematic?