Exam 2 MC

Consider the Animal, Fish, and Goldfish classes shown below. Which of the following object declarations will compile without error?

public class Animal

{

/* no constructors or other methods have been declared */

}

public class Fish extends Animal

{

/* no constructors or other methods have been declared */

}

public class Goldfish extends Fish

{

/* no constructors or other methods have been declared */

}

I. Goldfish glub = new Fish();

II. Animal glub = new Fish();

III. Fish glub = new Goldfish();

• (A) I only

• (B) II only

• (C) III only

• (D) I and II only

• (E) II and III only

Assume that list has been instantiated as an ArrayList of integers containing [6, 2, 9] . What are the contents of list after the code is executed?

list.remove(2);

list.add(1, 4);

list.add(5);

list.set(2, 7);

• (A) [6, 2, 7, 5]

• (B) [6, 4, 2, 7, 5]

• (C) [4, 7, 9, 5]

• (D) [6, 4, 7, 5]

• (E) [4, 7, 6, 9, 5]

A sorted array of integers containing 2000 elements is to be searched for key using a binary search method. Assuming key is in the array, what is the maximum number of iterations needed to find key?

• (A) 8

• (B) 10

• (C) 100

• (D) 2000

• (E) 11

Which of the following code segments creates a 7 x 9 array of integers and fills every space in the array with multiples of two (not including the value 0)?

I. int[][] arr = new int [7][9];

II. int[][] arr = new int [7][9];

int count = 1;

for(int i = 0; i < arr.length; i++)

{

for(int j = 0; j < arr[0].length; j++)

{

arr[i][j] = count * 2;

count++;

}

}

III. int[][] arr = new int [7][9];

int count = 1;

int row = 0;

int col = 0;

while (row < arr.length && col < arr[0].length)

{

arr[row][col] = count * 2;

row++;

col++;

count++;

}

• (A) I only

• (B) II only

• (C) II and III only

• (D) I and II only

• (E) III only

Consider the method printString shown below. What is printed as a result of printString(“sandwich”)?

public void printString(String s)

{

if (s.length() > 0)

{

printString(s.substring(1));

System.out.print(s.substring(0, 1));

}

}

• (A) hciwdnas

• (B) sandwich

• (C) andwichandwichndwichdwichwichichchh

• (D) hchichwichdwichndwichandwich

• (E) Nothing is printed because an infinite loop occurs

The Dog class is shown below. The GoldenRetriever class inherits from the Dog class. Which methods and variables does the GoldenRetriever class inherit?

public class Dog

{

private int numLegs = 4;

private String name = "Spot";

public Dog(String theName)

{

/* implementation not shown */

}

public String bark()

{

return "Woof!";

}

public String getName()

{

return name;

}

public int getNumLegs()

{

return numLegs;

}

}

I. public Dog(String theName)

II. bark()

III. getName()

IV. private String name;

• (A) I only

• (B) I and II only

• (C) III only

• (D) II and III only

• (E) I, II, III, and IV

Which of these loops will output 02468?

I. for (int i = 0; i <= 8; i++)

{

System.out.print(i);

}

II. int i = 0;

while (i < 8)

{

i +=2;

System.out.print(i);

}

III. for (int i = 0; i <= 8; i +=2)

{

System.out.print(i);

}

• (A) I only

• (B) II only

• (C) III only

• (D) I and II only

• (E) I, II, and III

Consider the following method mystery. Assuming x is an integer greater than 1, in which case does mystery result in an infinite loop?

public int mystery(int x, int y)

{

if (x <= y)

return x;

else

return mystery(x, y * 10);

}

• (A) y is greater than 1

• (B) y is less than or equal to 0

• (C) y is greater than x

• (D) all of the above

• (E) none of the above

Consider the following classes Cat and FluffyCat. What is the result of executing the following code? Cat obj = new FluffyCat();

obj.display();

public class Cat

{

public String display()

{

System.out.print("Cats! ");

}

}

public class FluffyCat extends Cat

{

public String display()

{

System.out.print("Cool!");

}

}

• (A) Cats!

• (B) Cats! Cool!

• (C) Cool!

• (D) Cool! Cats!

• (E) The code results in an error.

14-3-10: Consider the class showMe, shown below. What is printed as a result of showMe(10)?

public static void showMe(int arg)

{

if (arg > 1)

{

showMe(arg - 1);

}

else

{

System.out.print(arg + " ");

}

}

• A) 1

• (B) 0

• (C) 10 9 8 7 6 5 4 3 2 1

• (D) 1 2 3 4 5 6 7 8 9 10

• (E) 10