WTN-12-QUIZ-3

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

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

• 2

• 4

• 8

• 16

What is the index variable for the element at the first row and first column in array

a?

.

• a[0][0]

• a[1][1]

• a[0][1]

• a[1][0]

Which of the following statements assigns the letter S to the third row and first column of a two-dimensional array named strGrid (assuming row-major order).

• strGrid[0][2] = "S";

• strGrid[1][3] = "S";

• strGrid[3][1] = "S";

• strGrid[2][0] = "S";

How would you get the value 6 out of the following array

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

• a[0][3]

• a[1][3]

• a[0][2]

• a[2][0]

Given the following code segment, what is the value of sum after this code executes?

int[][] matrix = { {1,1,2,2},{1,2,2,4},{1,2,3,4},{1,4,1,2}};

int sum = 0; int col = matrix[0].length - 2; for (int row = 0; row < 4; row++) { sum = sum + matrix[row][col]; }

• 4

• 8

• 9

• 12

What are the contents of mat after the following code segment has been executed?

int [][] mat = new int [4][3]; for (int row = 0; row < mat.length; row++) { for (int col = 0; col < mat[0].length; col++) { if (row < col) mat[row][col] = 1; else if (row == col) mat[row][col] = 2; else mat[row][col] = 3; } }

• { {2 3 3}, {1 2 3}, {1 1 2}, {1 1 1}}

• { {2 1 1}, {3 2 1}, {3 3 2}, {3 3 3}}

• { {2 1 1 1}, {3 2 1 1}, {3 3 2 1}}

• { {2 3 3 3}, {1 2 3 3}, {1 1 2 3}}

Given the following code segment, what is the value of sum after this code executes?

int[][] m = { {1,1,1,1},{1,2,3,4},{2,2,2,2},{2,4,6,8}}; int sum = 0; for (int k = 0; k < m.length; k++) { sum = sum + m[m.length-1-k][1]; }

A. 4 B. 6 C. 9 D. 10

• 4

• 6

• 9

• 10

What are the contents of arr after the following code has been executed?

int[][] arr = { {3,2,1},{1,2,3}}; int value = 0; for (int row = 1; row < arr.length; row++) { for (int col = 1; col < arr[0].length; col++) { if (arr[row][col] % 2 == 1) { arr[row][col] = arr[row][col] + 1; } if (arr[row][col] % 2 == 0) { arr[row][col] = arr[row][col] * 2; } } }

• { {6, 4, 2}, {2, 4, 6}}

• { {3, 4, 2}, {2, 4, 8}}

• { {3, 2, 1}, {1, 4, 6}}

• { {3, 2, 1}, {1, 4, 8}}

Analyze the following code:

public class Test {

public static void main(String[] args) {

boolean[][] x = new boolean[3][];

x[0] = new boolean[1]; x[1] = new boolean[2];

x[2] = new boolean[3];

System.out.println("x[2][2] is " + x[2][2]);

}

}

• The program has a compile error because new boolean[3][] is wrong.

• . The program has a runtime error because x[2][2] is null.

• The program runs and displays x[2][2] is false.

• The program runs and displays x[2][2] is null.

Suppose a method p has the following heading:

public static int[][] p()

What return statement may be used in p()?

• return 1;

• return new int[][]{{1, 2, 3}, {2, 4, 5}};

• return new int[]{1, 2, 3};

• return int[]{1, 2, 3};