Multiplying 2D arrays in Java

Question

I'm having some trouble with the question below, not entirely sure if its write as I can't figure out how to call the method in the driver method to print the result.

(Question) Create a Method with header:

public static int[][] multiplyArrays(int[][] a, int[][] b)

The above method will multiply two 2D arrays referred to by a and b, and return a 2D array reference of a × b. Multiplying two 2D array work on the following algebraic expression to find out the resultant array: result[i][j]= a[i][k] * b[k][j]

Hint: In this case, inside the method, declare a 2D int[][] array reference variable and instantiate it with a size of a.length x b[0].length. They complete the rest using the series multiplication. This is an application of nested loop. The outermost loop will run from 0 to N. The middle loop will run for index i and the innermost one will run for index j.

My code so far:

public static int[][] multiplyArrays(int[][] a, int[][] b) {   
  var aNumRows = a.length;
  var aNumCols = a[0].length;
  var bNumCols = b[0].length;
  int[][] m = new int[aNumRows][bNumCols];
  for (var r = 0; r < aNumRows; ++r) {
      for (var c = 0; c < bNumCols; ++c) {
          m[r][c] = 0;
          for (var i = 0; i < aNumCols; ++i) {
              m[r][c] += a[r][i] * b[i][c];
              System.out.printf("%3d",r, c);
          }
      }
  }
  return m;
}

Answer 1

Since the method you defined is static, you could simply use classname.multiplyArrays(a, b) ; where a and b are the names of the variables in your driver method.