Syntax for creating a two-dimensional array

java multidimensional-array
AppSensei picture AppSensei · Sep 1, 2012 · Viewed 1.6M times · Source

Consider:

int[][] multD = new int[5][];
multD[0] = new int[10];

Is this how you create a two-dimensional array with 5 rows and 10 columns?

I saw this code online, but the syntax didn't make sense.

Answer

obataku picture obataku · Sep 1, 2012

Try the following:

int[][] multi = new int[5][10];

... which is a short hand for something like this:

int[][] multi = new int[5][];
multi[0] = new int[10];
multi[1] = new int[10];
multi[2] = new int[10];
multi[3] = new int[10];
multi[4] = new int[10];

Note that every element will be initialized to the default value for int, 0, so the above are also equivalent to:

int[][] multi = new int[][]{
  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
};

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