Added tester

MatrixExample.java

@@ -20,7 +20,7 @@ public static void main(String[] args) {
 
         System.out.println("result length: " + result.length + " x " + result[0].length);
         for (int i = 0; i < result.length; i++) {
-            for (int j = 0; j < result[i].length; i++) {
+            for (int j = 0; j < result[i].length; j++) {
                 System.out.print(result[i][j] + " ");
             }
             System.out.println();

MatrixExampleTester.java

@@ -0,0 +1,125 @@
+import java.util.ArrayList;
+
+public class MatrixExampleTester {
+    public static void main(String[] args) {
+        System.out.println("Matrix Multiplication works: " + testMultiplyMatricies());
+        System.out.println("Matrix Generation works: " + testGenerateMatricies());
+    }
+
+
+ /*
+  * tests if matrix multiplication is working by comparing results
+  * to kown matrix multiplication equation results
+  */
+    private static boolean testMultiplyMatricies() {
+
+        int[][] A1 = {
+                {1, 8, 3},
+                {8, 4, 5},
+                {6, 2, 7}
+        };
+
+        int[][] B1 = {
+                {6, 7, 4},
+                {1,3,2},
+                {5, 9, 8}
+        };
+
+        int[][] result1 = {
+               {29, 58, 44},
+               {83, 120, 84},
+                {73, 111, 84}
+        };
+
+        int[][] A2 = {
+               {1, 5, 4},
+               {9, 3, 8}
+        };
+
+        int[][] B2 = {
+                {6, 7},
+                {1, 3},
+                {5, 9}
+        };
+
+        int[][] result2 = {
+                {31, 58},
+                {97, 144}
+        };
+
+
+        int[][] A3 = {
+                {2, 0, -3},
+                {1, 4, 5}
+        };
+
+        int[][] B3 = {
+                {3, 1},
+                {-1, 0},
+                {4, 2}
+        };
+
+        int[][] result3 = {
+                {-6, -4},
+                {19, 11}
+        };
+
+        int[][] matrix1 = MatrixExample.multiplyMatrices(A1, B1);
+        int[][] matrix2 = MatrixExample.multiplyMatrices(A2, B2);
+        int[][] matrix3 = MatrixExample.multiplyMatrices(A3, B3);
+        // printMatrix(matrix1);
+        // System.out.println();
+        // printMatrix(matrix2);
+        // System.out.println();
+        // printMatrix(matrix3);
+
+
+        if (!matriciesAreTheSame(matrix1, result1) || !matriciesAreTheSame(matrix2, result2) || !matriciesAreTheSame(matrix3, result3))
+            return false;
+        return true;
+    }
+
+    private static void printMatrix (int[][] result) {
+        for (int i = 0; i < result.length; i++) {
+            for (int j = 0; j < result[i].length; j++) {
+                System.out.print(result[i][j] + " ");
+            }
+            System.out.println();
+        }
+    }
+
+    /*
+     * Returns true if the generator creates the correct length
+     * matricies, and if each matrix is unique
+     * tests 10 matricies to ensure that this is true
+     */
+    private static boolean testGenerateMatricies() {
+        ArrayList<int[][]> matricies = new ArrayList<>();
+        int rows = (int) (Math.random() * 10 + 1);
+        int cols = (int) (Math.random() * 10 + 1);
+        for (int i = 0; i < 10; i++) {
+            int[][] matrix = MatrixExample.generateRandomMatrix(rows, cols);
+            if (matrix.length != rows || matrix[0].length != cols)
+                return false;
+            for (int[][] other : matricies) {
+                if (matriciesAreTheSame(other, matrix))
+                    return false;
+            }
+            matricies.add(matrix);
+        }
+        return true;
+    }
+
+    // Returns true if two matricies are identical
+    private static boolean matriciesAreTheSame(int[][] one, int[][] two) {
+        if (one.length != two.length || one[0].length != two[0].length)
+            return false;
+        for (int r = 0; r < one.length; r++) {
+            for (int c = 0; c < one[0].length; c++) {
+                if (one[r][c] != two[r][c])
+                    return false;
+            }
+        }
+        return true;
+    }
+}