Chapter 2 Review

The code segment below is intended to calculate the circumference c of a circle with the diameter d of 1.5. The circumference of a circle is equal to its diameter times pi.

/* missing declarations */

c = pi * d;

Which of the following variable declarations are most appropriate to replace /* missing declarations */ in this code segment?

• int pi = 3.14159;

  int d = 1.5;

  final int c;

• final int pi = 3.14159;

  int d = 1.5;

  int c;

• final double pi = 3.14159;

  double d = 1.5;

  double c;

• double pi = 3.14159;

  double d = 1.5;

  final double c = 0.0;

• final double pi = 3.14159;

  final double d = 1.5;

  final double c = 0.0;

Consider the following code segment.

int x = 5;

int y = 6;

/* missing code */

z = (x + y) / 2;

Which of the following can be used to replace /* missing code */ so that the code segment will compile?

I. int z = 0;

II. int z;

III. boolean z = false;

• I ONLY

• II ONLY

• I AND II ONLY

• II AND III ONLY

• I, II, AND III

Consider the following code segment.

int a = 5;

int b = 8;

int c = 3;

System.out.println(a + b / c * 2);

What is printed as a result of executing this code?

• 2

• 6

• 8

• 9

• 14

The following code segment is intended to interchange the values of the int variables x and y. Assume that x and y have been properly declared and initialized.

int temp = x;

/* missing code */

Which of the following can be used to replace /* missing code */ so that the code segment works as intended?

• x = y;

  x = temp;

• x = y;

  y = temp;

• y = x;

  x = temp;

• y = x;

  temp = y;

• y = x;

  temp = x;

Consider the following code segment, which is intended to print the digits of the two-digit int number num in reverse order. For example, if num has the value 75, the code segment should print 57. Assume that num has been properly declared and initialized.

/* missing code */

System.out.print(onesDigit);

System.out.print(tensDigit);

Which of the following can be used to replace /* missing code */ so that the code segment works as intended?

• int onesDigit = num % 10;

  int tensDigit = num / 10;

• int onesDigit = num / 10;

  int tensDigit = num % 10;

• int onesDigit = 10 / num;

  int tensDigit = 10 % num;

• int onesDigit = num % 100;

  int tensDigit = num / 100;

• int onesDigit = num / 100;

  int tensDigit = num % 100;

Which of the following expressions evaluate to 7 ?

I.9 + 10 % 12

II. (9 + 10) % 12

III. 9 – 2 % 12

• I ONLY

• II ONLY

• I AND III

• II AND III

• I, II, AND III

Consider the following code segment.

int a = 5;

int b = 4;

int c = 2;

a *= 3;

b += a;

b /= c;

System.out.print(b);

What is printed when the code segment is executed?

• 2

• 4

• 9

• 9.5

• 19

Consider the following code segment.

num += num;

num *= num;

Assume that num has been previously declared and initialized to contain an integer value. Which of the following best describes the behavior of the code segment?

• The value of num is two times its original value.

• The value of num is the square its original value.

• The value of num is two times the square of its original value.

• The value of num is the square of twice its original value.

• It cannot be determined without knowing the initial value of num.

Consider the following code segments. Code segment 2 is a revision of code segment 1 in which the loop increment has been changed.

Code Segment 1

int sum = 0;

for (int k = 1; k <= 30; k++) {

sum += k; }

System.out.println("The sum is: " + sum);

Code Segment 2

int sum = 0;

for (int k = 1; k <= 30; k = k + 2) {

sum += k; }

System.out.println("The sum is: " + sum);

Code segment 1 prints the sum of the integers from 1 through 30, inclusive. Which of the following best explains how the output changes from code segment 1 to code segment 2 ?

• Code segment 1 and code segment 2 will produce the same output.

• Code segment 2 will print the sum of only the even integers from 1 through 30, inclusive because it starts sum at zero, increments k by twos, and terminates when k exceeds 30.

• Code segment 2 will print the sum of only the odd integers from 1 through 30, inclusive because it starts k at one, increments k by twos, and terminates when k exceeds 30.

• Code segment 2 will print the sum of only the even integers from 1 through 60, inclusive because it starts sum at zero, increments k by twos, and iterates 30 times.

• Code segment 2 will print the sum of only the odd integers from 1 through 60, inclusive because it starts k at one, increments k by twos, and iterates 30 times.

Consider the following code segment.

int count = 0;

for (int k = 0; k < 10; k++) {

count++; }

System.out.println(count);

Which of the following code segments will produce the same output as the code segment above?

• int count = 0;

  for (int k = 1; k < 10; k++) {

  count++;}

  System.out.println(count);

• int count = 1;

  for (int k = 1; k <= 10; k++) {

  count++; }

  System.out.println(count);

• int count = 1;

  for (int k = 0; k <= 9; k++){

  count++;}

  System.out.println(count);

• int count = 0;

  for (int k = 9; k >= 0; k--){

  count++;}

  System.out.println(count);

• int count = 0;

  for (int k = 10; k >= 0; k--){

  count++;}

  System.out.println(count);