AP CSA Unit 8 Review: 2D Arrays

Which of the following statements correctly declares a two-dimensional integer array?

• int Matrix[ ] = new int[5,4];

• int Matrix[ ]; Matrix = new int[5,4];

• int Matrix[ ][ ] = new int[5][4];

• int Matrix[ ][ ] = int[5][4];

How would you get the value 6 out of the following array int[][] a = {{2, 4, 6, 8}, {1, 2, 3, 4}};? Remember each set of curly braces represents a row, or a single dimensional array.

• a [0][3]

• a [1][3]

• c) a[0][2]

• d) a[2][0]

• e) a[3][1]

How many columns does a have if it is created as follows

int[][] a = {{2, 4, 6, 8}, {1, 2, 3, 4}};?

• 3

• 4

• 2

• 1

Given the code, what is the value of things.length ?

• 4

• 3

• 12

• 7

Given the code, what is in values[2][1] ?

• 7.9

• 9.2

• 7.3

• 0.5

Given the code, what is in values[0][1] ?

• 1.2

• 9.2

• 9.0

• 4.8

What value is at index 1 in this array?  String[] names = {"Mack", "Dennis", "Dee", "Charlie"};

• Mack
• Dennis
• Dee
• Charlie

Examine the following:

double[][] values =

{ {1.2, 9.0, 3.2},

{9.2, 0.5, 1.5, -1.2},

{7.3, 7.9, 4.8} } ;

what is in values[3][0] ?

• 1.2

• 9.2

• 7.3

• No such element exists in array

How can I store the value 10 into the first row, third column of my array that I have declared as int numbers[10][10]?

• int numbers[1][2] = 10;

• numbers[0][2] = 10;

• numbers[2][3] = 10;

• numbers[1][3] = 10

How can I store the value 10 into the second row, first column of my array that I have declared as int numbers[10][10]?

• int numbers[1][2] = 10;

• numbers[1][2] = 10;

• numbers[2][3] = 10;

• numbers[1][0] = 10