Java Chapter 7 - Arrays & Array Lists

traversing all elements in an array

What is the enhanced for loop convenient for?

int[] numarray = new int[10];

a statement for defining an integer array named numarray of ten elements

maintain a companion variable that stores the current number of elements

an array myArray is only partially filled, to keep track of the current number of elements you would...

1

consider the following code snippet: ArrayList<Double> somedata = new ArrayList<Double>(); somedata.add(10.5); the size of the array list somedata after the given code snippet is executed is:

5

consider the following code snippet: int cnt = 0; int[][] numarray = new int[2][3]; for (int i = 0; i < 3; i++) { for (int j = 0; j < 2; j++) { numarray[j][i] = cnt; cnt++; } } the value of numarray[1][2] after the code snippet is executed is:

System.out.println(arr[1][1]);

consider the following code snippet: int[][] arr = { { 13, 23, 33 }, { 14, 24, 34 } }; the appropriate statement that displays the value 24 is:

Arrays.sort(data);

considering the following code snippet: String[] data = { "123", "ghi", "jkl", "def", "%&*" }; the statement that sorts the data array in ascending order

for (String str : arr)

the correct enhanced for loop to iterate over the array without using an index variable (fill in the blank line). String[] arr = { "abc", "def", "ghi", "jkl" }; _________ { System.out.print(str); }

methods that return an array cannot specify its size

the method header public static int[5] meth(int[] arr, int[] num) is invalid because:

30

the number of elements that can be stored in a two-dimensional 5 by 6 array

6

the number of elements that can be stored in an array of dimension 2 by 3

6

the output of the code snippet below is: int[][] arr = { { 1, 2, 3, 0 }, { 4, 5, 6, 0 }, { 0, 0, 0, 0 } }; int val = arr[1][2] + arr[1][3]; System.out.println(val);

3040

the output of the code snippet: int[] myarray = { 10, 20, 30, 40, 50 }; System.out.print(myarray[2]); System.out.print(myarray[3]);

2345

the output of the given code snippet? int[] mynum = new int[5]; for (int i = 1; i < 5; i++) { mynum[i] = i + 1; System.out.print(mynum[i]); }

aaa 3

the output of this code snippet is: public static void main(String[] args) { String[] arr = { "aaa", "bbb", "ccc" }; mystery(arr); System.out.println(arr[0] + " " + arr.length); } public static void mystery(String[] arr) { arr = new String[5]; arr[0] = "ddd"; }

code snippet causes a bounds error

the result of executing this code snippet: int[] marks = { 90, 45, 67 }; for (int i = 0; i <= 3; i++) { System.out.println(marks[i]); }

the array values is not modified

the result of the following code: for (double element : values) { element = 0; }

many people feel it is less intimidating than drawing diagrams

the use of physical objects helpful in algorithm design because:

1

the value of the count variable after the execution of the given code snippet: ArrayList<Integer> num = new ArrayList<Integer>(); num.add(1); num.add(2); num.add(1); int count = 0; for (int i = 0; i < num.size(); i++) { if (num.get(i) % 2 == 0) { count++; } }

take the length of the array minus the number of elements currently in the array

to determine the number of slots in a partially filled array, that are not currently used you would...

remove an element

to process an array of values and eliminate any potential duplicate values stored in the array, the array algorithm that might be adapted for this us:

1 86 24 4

what will be printed by the statements below is: int[] values = { 1, 2, 3, 4}; values[2] = 24; values[values[0]] = 86; for (int i = 0; i < values.length; i++) System.out.print (values[i] + " ");

2

what will be printed by the statements below is: int[] values = { 10, 24, 3, 64}; int position = 0; for (int i = 1; i < values.length; i++) if (values[i] > values[position]) position = i; System.out.print (position);

the program will not compile

what will happen if you confuse the method required for checking the length of a string and using size() instead of length(), is:

the array list contains at least one element

what you should check for when calculating the smallest value in an array list is:

auto-boxing

when an integer literal is added to an array list declared as ArrayList<Integer>, the action that Java performs is:

when the elements of the array are ordered

when is the binary search faster than the linear search?

the number of inputs may not be known in advance

when reading inputs, why might it be necessary to "grow" an array because:

to replace the element to be deleted with the last element in the array

when the order of the elements is unimportant, the most efficient way to remove an element from an array is:

it stays the same

when two cards in a deck of cards shuffle their position what happens to the size of the array is: