GENERICS - Introduction to Java Programming: Comprehensive Version - page 754

20 E[][] result =
21 (E[][]) new Number[matrix1.length][matrix1[ 0 ].length];
22
23 // Perform addition
24 for ( int i = 0 ; i < result.length; i++)
25 for ( int j = 0 ; j < result[i].length; j++) {
26 result[i][j] = add(matrix1[i][j], matrix2[i][j]);
27 }
28
29 return result;

30 }
31
32

/** Multiply two matrices */

33 public E[][] multiplyMatrix(E[][] matrix1, E[][] matrix2) {

multiply two matrices

34 // Check bounds

35 if (matrix1[ 0 ].length != matrix2.length) {

36 throw new RuntimeException(

37 "The matrices do not have compatible size" );

38 }
39
40 // Create result matrix
41 E[][] result =
42 (E[][]) new Number[matrix1.length][matrix2[ 0 ].length];
43
44 // Perform multiplication of two matrices
45 for ( int i = 0 ; i < result.length; i++) {
46 for ( int j = 0 ; j < result[ 0 ].length; j++) {
47 result[i][j] = zero();
48
49 for ( int k = 0 ; k < matrix1[ 0 ].length; k++) {
50 result[i][j] = add(result[i][j],
51 multiply(matrix1[i][k], matrix2[k][j]));
52 }
53 }
54 }
55
56 return result;

57 }
58
59 /** Print matrices, the operator, and their operation result */
60 public static void printResult(
61 Number[][] m1, Number[][] m2, Number[][] m3, char op) {
62 for ( int i = 0 ; i < m1.length; i++) {
63 for ( int j = 0 ; j < m1[ 0 ].length; j++)
64 System.out.print( " " + m1[i][j]);
65
66 if (i == m1.length / 2 )
67 System.out.print( " " + op + " " );
68 else
69 System.out.print( " " );
70
71 for ( int j = 0 ; j < m2.length; j++)
72 System.out.print( " " + m2[i][j]);
73
74 if (i == m1.length / 2 )
75 System.out.print( " = " );
76 else
77 System.out.print( " " );
78
79

display result

for ( int j = 0 ; j < m3.length; j++)