CAI710: WQ1

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

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A two-dimensional array arr is to be created with the following contents.

boolean[][] arr = {{false, true, false} ,

{false, false, true}};

Which of the following code segments can be used to correctly create and initialize arr ?

• boolean arr[][] = new boolean[2][3];

  arr[0][1] = true;

  arr[1][2] = true;

• boolean arr[][] = new boolean[2][3];

  arr[1][2] = true;

  arr[2][3] = true;

• boolean arr[][] = new boolean[3][2];

  arr[0][1] = true;

  arr[1][2] = true;

• boolean arr[][] = new boolean[3][2];

  arr[1][0] = true;

  arr[2][1] = true;

• boolean arr[][] = new boolean[3][2];

  arr[2][1] = true;

  arr[3][2] = true;

Consider the following code segment, which is intended to declare and initialize the two-dimensional (2D) String array things.

/* missing code */ = {{"spices", "garlic", "onion", "pepper"},

{"clothing", "hat", "scarf", "gloves"},

{"plants", "tree", "bush", "flower"},

{"vehicles", "car", "boat", "airplane"}};

Which of the following could replace /* missing code */ so that things is properly declared?

• new String[][] things

• new(String[][]) things

• String[] String[] things

• String[][] things

• [][]String things

Consider the following code segment.

int[][] array2D = {{1, 2, 3, 4},

{5, 6, 7, 8},

{9, 10, 11, 12},

{13, 14, 15, 16}};

for (int[] i : array2D){

for (int x : i){

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

}

System.out.println(" ");

}

How many times will the statement System.out.print(x + " ") be executed?

• 3 times

• 4 times

• 6 times

• 12 times

• 16 times

Assume that a two-dimensional (2D) array arr of String objects with 3 rows and 4 columns has been properly declared and initialized.

Which of the following can be used to print the elements in the four corner elements of arr ?

• System.out.print(arr[0, 0] + arr[0, 3] + arr[2, 0] + arr[2, 3]);

• System.out.print(arr[1, 1] + arr[1, 4] + arr[3, 1] + arr[3, 4]);

• System.out.print(arr[0][0] + arr[0][2] + arr[3][0] + arr[3][2])

• System.out.print(arr[0][0] + arr[0][3] + arr[2][0] + arr[2][3]);

• System.out.print(arr[1][1] + arr[1][4] + arr[3][1] + arr[3][4]);

Consider the following code segment, where letters is a two-dimensional (2D) array that contains possible letters. The code segment is intended to print "DIG".

String[][] letters = {{"A", "B", "C"},

{"D", "E", "F"},

{"G", "H", "I"}};

System.out.println( /* missing code */ );

Which of the following could replace /* missing code */ so that the code segment works as intended?

• letters[1][0] + letters[2][2] + letters[2][0]

• letters[2][1] + letters[3][3] + letters[3][1]

• letters[2][0] + letters[2][2] + letters[1][0]

• letters[1][2] + letters[3][3] + letters[1][3]

• letters[0][1] + letters[2][2] + letters[0][2]

Consider the following code segment, where nums is a two-dimensional (2D) array of integers. The code segment is intended to print "test1234".

System.out.print("test" + nums[0][0] + nums[1][0] + nums[1][1] + nums[0][1]);

Which of the following code segments properly declares and initializes nums so that the code segment works as intended?

• int[][] nums = {{1, 2}, {3, 4}};

• int[][] nums = {{1, 4}, {2, 3}};

• int[][] nums = {{1, 2}, {4, 3}};

• int[][] nums = {{1, 3}, {2, 4}};

• int[][] nums = {{1, 4}, {3, 2}};

Consider the following code segment.

int[][] arr = {{1, 2, 3},

{4, 5, 6},

{7, 8, 9},

{3, 2, 1}};

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

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

System.out.print(arr[j][k] + " ");

}

System.out.println();

}

What output is printed when the code segment is executed?

• 2 3

  6

• 1 2 3

  4 5

  7

• 1 2 3

  5 6

  9

• 1 4 7

  5 8

  9

• 1 2 3

  5 6

  9

  1