Java basic series-6, two-dimensional array

Class arraydemo {public static void main (string [] ARGs) {int [] [] arr = new int [3] [4]; // defines a two-dimensional array named arr. The two-dimensional array has three one-dimensional arrays, each of which has four elements. System. out. println ("arr =" + ARR); // The result is: arr = [[I @1fb8ee3System.out.println ("arr [0] =" + arr [0]); // The result is: arr [0] = [I @61de33System.out.println ("arr [0] [0] =" + arr [0] [0]); // The result is: arr [0] [0] = 0int [] [] arr2 = new int [3] []; system. out. println ("arr2 =" + arr2); // The result is: arr2 = [[I @61de33System.out.println ("arr2 [0] =" + arr2 [0]); // The result is: arr2 [0] = nullint [] [] arr3 = new int [3] []; arr3 [0] = new int [3]; arr3 [1] = new int [1]; arr3 [2] = new int [2]; system. out. println ("arr3 =" + arr3); // The result is: arr3 = [[I @14318bbSystem.out.println ("arr3 [0] =" + arr3 [0]); // The result is: arr3 [0] = [I @ca0b6System.out.println ("arr3 [0] [0] =" + arr3 [0] [0]); // The result is: arr3 [0] [0] = 0system. out. println ("-----------------------------------"); int [] [] arr4 = new int [3] [4]; system. out. println ("arr4.length =" + arr4.length); // print the length of the two-dimensional array 3; system. out. println ("arr4 [0]. length = "+ arr4 [0]. length); // print the length of the first one-dimensional array in a two-dimensional array 4; system. out. println ("---------------------------------"); int [] [] arr5 = {,}, {,}, {6, 1, 8}; int sum = 0; for (INT x = 0; x <arr5.length; X ++) {for (INT y = 0; y <arr5 [X]. length; y ++) {sum = sum + arr5 [x] [Y] ;}} system. out. println ("sum =" + sum );}}

Exercise: Two-dimensional array Definition

 
Int [] X, Y []; // X one-dimensional, y two-dimensional. // Equivalent to int [] X; int [] Y [];