Which two are valid declarations of a two-dimensional array?

Question

Options

• Aint [][] array2D;
• Bint [2][2] array2D;
• Cint array2D[][];
• Dint[] array2D[];
• Eint[][] array2D[];

• A
  92% (44)
• B
  4% (2)
• C
  2% (1)
• E
  2% (1)

Explanation

In Java, the bracket notation [] can be placed after the type, after the variable name, or split between both. Option A (int [][] array2D) uses the conventional style with both bracket pairs after the type, while option D (int[] array2D[]) splits them - one pair after int and one after the variable name - which Java's spec explicitly permits, making both unambiguously valid 2D array declarations.

B is wrong because you cannot specify array sizes inside the brackets at declaration time (int [2][2] array2D is illegal); dimensions belong in the instantiation (new int[2][2]), not the declaration. E is wrong because placing brackets after both int[][] and the variable name (int[][] array2D[]) results in a 3D array (int[][][]), not a 2D one. C (int array2D[][]) is actually valid Java syntax and is commonly cited as correct in other exam versions - its inclusion as a distractor here may reflect a flaw in this specific question's answer key.

Memory tip: Think of the brackets as "attaching" to the variable from either side - left (on the type) or right (on the name), or both - as long as the total bracket pairs equal the number of dimensions. Watch out for size values inside declaration brackets (illegal) and extra bracket pairs that silently add a dimension.

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