add matrix transpose

campbe13 · campbe13 · commit 9d3e0cf21e4f · 2018-04-09T00:29:23.000Z
diff --git a/fromslides/S14-2d-Arrays/ArrayTranspose.java b/fromslides/S14-2d-Arrays/ArrayTranspose.java
@@ -0,0 +1,81 @@
+//package fromslides.S15;
+
+/**
+ * Create a 2d array, sum it
+ *
+ * @author     pmc
+ * @version    slide deck 15
+ */
+
+public class ArrayTranspose {
+    public static void main(String[] args) {
+        int[][] a = {
+            { 0,1,3,2 }, 
+            { 1,4,8,7}, 
+            { 9, 7,0,3 }
+        };
+        int[][] b = {
+            { 0,1,3,2 }, 
+            { 1,4,8,7, 5, 6 }, 
+            { 9, 7,0,3 }
+        };
+        int  transposedArray[][];
+
+        transposedArray = transpose(a);
+        displayArray("Original ", a);
+        displayArray("Transposed ", transposedArray);
+        
+        if (transposedArray == null)
+            System.out.println("Original Array is not rectangular");
+        else displayArray("Transposed ", transposedArray); 
+
+        transposedArray = transpose(b);
+        displayArray("Original ", b);
+        
+        if (transposedArray == null)
+            System.out.println("\nOriginal Array is not rectangular");
+        else displayArray("Transposed ", transposedArray); 
+
+        } // end main
+    public static int[][] transpose (int[][] array) {
+           //check if rectangular  ​
+            int col = array[0].length;
+            for (int i = 1; i< array.length; i++)
+                {
+                    if (array[i].length != col)
+                        return null;
+                }
+        // if we get here it must be rectangular so transpose​
+           int[][] t = new int[array[0].length][array.length];
+           for (int i = 0; i < t.length; i ++)
+                    {
+                        for (int j=0; j< t[i].length; j++)
+                            t[i][j] = array[j][i];
+                    }
+                    return t;
+                    }
+/**
+        * display the array with a message 
+        * @param name   message String  integer array
+        * @param arry    integer array
+        **/ 
+public static void displayArray(String name, int arry[])   {
+    System.out.println("\nArray: "+name);
+    for (int i=0; i < arry.length; i++)
+     System.out.print("["+i+"] = "+ arry[i]+" ");
+}
+/**
+        * display the array with a message 
+        * @param name   message String  integer array
+        * @param arry    integer array
+        **/ 
+public static void displayArray(String name, int arry[][])   {
+    System.out.println("\nArray: "+name);
+    for (int row=0; row < arry.length; row++)   {
+        System.out.printf("[ ");
+       for (int col = 0; col < arry[row].length; col++ )
+             System.out.print(arry[row][col] +" ");
+         System.out.printf("]\n");
+     }
+}
+} // end class
