ArrayLists

What is printed as a result of executing the following code?

ArrayList<Integer> alist = new ArrayList<Integer>();

alist.add(1);

alist.add(2);

alist.remove(1);

alist.add(1, 3);

alist.set(1, 4);

alist.add(5);

System.out.println(alist);

• [1, 4, 5]

• [1, 4, 3, 5]

• [2, 4, 5]

• [2, 4, 3, 5]

Which statement below is the correct way to retrieve the first element in the nums ArrayList?

• nums.get(0)

• nums[0]

• nums(0)

• nums[1]

Given the ArrayList nums with the values [3, 7, 6, 0], what code below is the proper way to change the 7 to be a 5?

• nums.set(1, 5)

• nums.set(7, 5)

• nums.set(5, 2)

• nums[2] = 5

What is printed as a result of executing the following code segment?

List<Integer> list1 = new ArrayList<Integer>();

list1.add(new Integer(1));

list1.add(new Integer(2));

list1.add(new Integer(3));

list1.set(2, new Integer(4));

list1.add(2, new Integer(5));

list1.add(new Integer(6));

System.out.println(list1);

• [1, 2, 3, 4, 5]

• [1, 2, 4, 5, 6]

• [1, 2, 5, 4 ,6]

• [1, 5,2, 4 ,6]

Given the following code and assume that nums initially contains [0, 0, 4, 2, 5, 0, 3], what will nums contain as a result of executing numQuest?

private List<Integer> nums;

// precondition: nums.size() > 0;

// nums contains Integer objects

public void numQuest()

{

int k = 0;

Integer zero = new Integer(0);

while (k < nums.size())

{

if (nums.get(k).equals(zero))

nums.remove(k);

else

k++;

}

}

• [0, 4, 2, 5, 3]

• [3, 5, 2, 4, 0, 0, 0]

• [0, 0, 0, 4, 2, 5, 3]

• [4, 2, 5, 3]

Which of the following best describes the behavior of process1 and process2 (shown below)?

public static List<Integer> process1(int n)

{

List<Integer> someList = new ArrayList<Integer>();

for (int k = 0; k < n; k++)

someList.add(k);

return someList;

}

public static List<Integer> process2(int n)

{

List<Integer> someList = new ArrayList<Integer>();

for (int k = 0; k < n; k++)

someList.add(k, k);

return someList;

}

• Both methods produce the same result, and process1 is faster than process2.

• The two methods produce different results and take the same amount of time.

• The two methods produce different results, and process1 is faster than process2.

• The two methods produce different results, and process2 is faster than process1.

• Both methods produce the same result and take the same amount of time.

What is printed as a result of executing the following code segment?

List<Integer> aList = new ArrayList<Integer>();

aList.add(new Integer(1));

aList.add(new Integer(2));

aList.add(1, new Integer(5));

aList.set(1, new Integer(4));

aList.add(new Integer(6));

aList.add(new Integer(3));

System.out.println(aList);

• [1, 2, 5, 4, 6, 3]

• [6, 5, 4, 3, 2, 1]

• [1, 2, 3, 4, 5, 6]

• [1, 4, 2, 6, 3]

• . [1, 2, 4, 6, 3]

What is printed as a result of executing the following code segment?

List<String> list1 = new ArrayList<String>();

list1.add("a");

list1.add("b");

list1.add(0,"c");

list1.set(1, "d");

list1.set(0, "e");

list1.add("b");

System.out.println(list1);

• [e, d, b]

• [e, d, b, b]

• [e, d, a, b, b]

• [e, d, a, b]

Assume that numList has been initialized with the following Integer objects: [5, 7, 8, 12]. Which of the following shows the values in numList after a call to mystery(11)?

private List<Integer> numList;

public void mystery(int value)

{

int i = 0;

while (i < numList.size() && numList.get(i) < value)

{

i++;

}

numList.add(i, value);

• [5, 7, 8, 12]

• [5, 7, 8, 11, 12]

• [11, 5, 7, 8, 12]

• [5, 7, 8, 12, 11]

• [5, 7, 11, 8, 12]

Consider the following method from the picture below. What is printed as a result of executing the code segment?

• [a, b, c, d, e, f]
• [a, c, e, d, f]
• [c, b, e, d, f]
• [c, b, e, f]