2D Arrays: Creation and Access Practice

Sample questions

5 of 27 — sign in to practice the rest with adaptive difficulty and mastery tracking.

1. Sample 1difficulty 2/5

   Which initializes:

   <code>1 2 3 4 5 6 </code></pre>

   • A

     int a[2][3] = {1,2,3,4,5,6};

   • B

     int[][] a = (1,2,3,4,5,6);

   • C

     int[][] a = new int[2][3]{1,2,3,4,5,6};

   • D

     int[][] a = {{1,2,3},{4,5,6}};

     check_circle

   Why

   Nested braces: outer = rows; inner = columns.

   View full solution & statsarrow_forward

2. Sample 2difficulty 2/5

   String[][] s = {{"a", "b"}, {"c", "d"}};
   System.out.println(s[0][1] + s[1][0]);

   What is printed?

   • A

     ac

   • B

     ab

   • C

     cd

   • D

     bc

     check_circle

   Why

   s[0][1] is "b" and s[1][0] is "c". Concatenation gives "bc".

   View full solution & statsarrow_forward

3. Sample 3difficulty 2/5

   Which declares a 3×4 int matrix?

   • A

     int[3][4] m;

   • B

     int[][] m = new int[3][4];

     check_circle
   • C

     int[][] m = new int(3,4);

   • D

     int m[3,4];

   Why

   Java syntax: <code>int[][] m = new int[rows][cols];</code>.

   View full solution & statsarrow_forward

4. Sample 4difficulty 2/5

   int[][] m = {{1, 2, 3}, {4, 5, 6}};
   System.out.println(m[1][2]);

   What is printed?

   • A

     6

     check_circle
   • B

     3

   • C

     5

   • D

     4

   Why

   m[1] is the second row {4, 5, 6}, and m[1][2] is the third element of that row, which is 6.

   View full solution & statsarrow_forward

5. Sample 5difficulty 2/5

   int[][] m = new int[2][3];
   System.out.println(m.length + " " + m[0].length);

   What is printed?

   • A

     2 3

     check_circle
   • B

     3 2

   • C

     2 2

   • D

     6 0

   Why

   new int[2][3] creates a 2-row, 3-column array. m.length is rows = 2, m[0].length is columns = 3.

   View full solution & statsarrow_forward