Question 1

Given the following code snippet, what should we change to have 26 alphabet characters in the string str?
String str = "";
For (char c = 'A'; c < 'Z'; c++)
{
Str = str + c;
}

Accepted Answer

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

Question 2

What is the last output line of the code snippet given below?
Int i = 5;
While (i >= 1)
{
Int num = 1;
For (int j = 1; j <= i; j++)
{
System.out.print(num + "**");
Num = num * 2;
}
System.out.println();
I = i - 1;
}

Accepted Answer

A)  No output 
B)  1**2 
C)  1**2**3 
D)  1**

Question 3

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

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

Question 4

Select the statement that correctly completes the loop in this code snippet.
Int years = 20;
Double balance = 10000;
While (years > 0)
{
__________
Double interest = balance * rate / 100;
Balance = balance + interest;
}

Accepted Answer

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

Question 5

What is the output of the code snippet given below?
Int i = 0;
While (i != 9)
{
System.out.println("" + i);
I = i + 2;
}

Accepted Answer

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 6

How many times does the following loop run?
Int i = 0;
Int j = 1;
Do
{
System.out.println("" + i + ";" + j);
I++;
If (i % 3 == 0)
{
J--;
}
}
While (j >= 1);

Accepted Answer

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

Question 7

Which statement about this code snippet is accurate?
Int years = 50;
Double balance = 10000;
Double targetBalance = 20000;
Double rate = 3;
For (int i = 1; i = targetBalance)
{
I = years + 1;
}
Else
{
Double interest = balance * rate / 100;
Balance = balance + interest;
}
}

Accepted Answer

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 8

What will be the result of running the following code fragment?
Int year = 0;
Double rate = 5;
Double principal = 10000;
Double interest = 0;
While (year < 10)
{
Interest = (principal * year * rate) / 100;
System.out.println("Interest " + interest);
}

Accepted Answer

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 9

Which of the following statements is correct about a sentinel?

Accepted Answer

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 10

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

A)  Exactly once 
B)  Exactly twice 
C)  Can't be determined 
D)  Always infinite loop

Question 11

What will be the range of the random numbers generated by the following code snippet?
Int r1 = (int) (Math.random() * 50) + 1;

Accepted Answer

A)  Between 1 and 49 
B)  Between 0 and 50 
C)  Between 0 and 49 
D)  Between 1 and 50

Question 12

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

Accepted Answer

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

Question 13

Is the following code snippet legal?
Boolean b = false;
Do
{
System.out.println("Do you think in Java?");
}
While (b != b);

Accepted Answer

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 14

What will be the output of the following code snippet?
Int i;
Int j;
For (i = 0; i  i; j--)
{
System.out.print("*");
}
System.out.println("");
}

Accepted Answer

A)  A rectangle with six rows and seven columns of asterisks. The number of rows increments by one on completion of one iteration of the inner loop. 
B)  A right triangle with six rows and seven columns of asterisks. The number of columns increments by one on completion of one iteration of the inner loop. 
C)  A rectangle with seven rows and six columns of asterisks. The number of rows increments by one on completion of one iteration of the inner loop. 
D)  An inverted right triangle with six rows and seven columns of asterisks. The number of columns decrements by one on completion of one iteration of the inner loop.

Question 15

What is the sentinel value in the following code snippet?
Public static void main(String[] args)
{
Int age = 0;
Int sumOfAges = 0;
Int stop = 1;
Scanner reader = new Scanner(System.in);
System.out.println("Enter an age (-1 to stop): ");
Age = reader.nextInt();
While (age != -1)
{
SumOfAges = sumOfAges + age;
System.out.println("Enter an age (-1 to stop): ");
Age = reader.nextInt();
}
System.out.println("Sum of ages " + sumOfAges);
Return 0;
}

Accepted Answer

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

Question 16

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

Accepted Answer

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

Question 17

How many times does the code snippet given below display "Loop Execution"?
Int i = 1;
While (i != 10)
{
System.out.println ("Loop Execution");
I++;
}

Accepted Answer

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

Question 18

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

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

Question 19

What is the output of the code fragment given below?
Int i = 0;
Int j = 0;
While (i < 27)
{
I = i + 2;
J++;
}
System.out.println("j=" + j);

Accepted Answer

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

Question 20

What is the outcome of the following code snippet?
Boolean val1 = true;
Boolean val2 = false;
While (val1)
{
If (val1)
{
System.out.println("Hello");
}
Val1 = val2;
}

Accepted Answer

A)  No output will be displayed because of 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.

Exam 4: Loops

Given the following code snippet, what should we change to have 26 alphabet characters in the string str? String str = ""; For (char c = 'A'; c < 'Z'; c++) { Str = str + c; }

What is the last output line of the code snippet given below? Int i = 5; While (i >= 1) { Int num = 1; For (int j = 1; j <= i; j++) { System.out.print(num + "**") ; Num = num * 2; } System.out.println() ; I = i - 1; }

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) ;

Select the statement that correctly completes the loop in this code snippet. Int years = 20; Double balance = 10000; While (years > 0) { __________ Double interest = balance * rate / 100; Balance = balance + interest; }

What is the output of the code snippet given below? Int i = 0; While (i != 9) { System.out.println("" + i) ; I = i + 2; }

How many times does the following loop run? Int i = 0; Int j = 1; Do { System.out.println("" + i + ";" + j) ; I++; If (i % 3 == 0) { J--; } } While (j >= 1) ;

What will be the result of running the following code fragment? Int year = 0; Double rate = 5; Double principal = 10000; Double interest = 0; While (year < 10) { Interest = (principal * year * rate) / 100; System.out.println("Interest " + interest) ; }

Which of the following statements is correct about a sentinel?

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) ;

What will be the range of the random numbers generated by the following code snippet? Int r1 = (int) (Math.random() * 50) + 1;

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

Is the following code snippet legal? Boolean b = false; Do { System.out.println("Do you think in Java?") ; } While (b != b) ;

What will be the output of the following code snippet? Int i; Int j; For (i = 0; i < 6; i++) { For (j = 7; j > i; j--) { System.out.print("*") ; } System.out.println("") ; }

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

How many times does the code snippet given below display "Loop Execution"? Int i = 1; While (i != 10) { System.out.println ("Loop Execution") ; I++; }

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 is the output of the code fragment given below? Int i = 0; Int j = 0; While (i < 27) { I = i + 2; J++; } System.out.println("j=" + j) ;

What is the outcome of the following code snippet? Boolean val1 = true; Boolean val2 = false; While (val1) { If (val1) { System.out.println("Hello") ; } Val1 = val2; }