Improving notes on 2D arrays.

Author: aubertc

source/code/snippets/2darrays.cs …arrayExercise/2DarrayExercise/Program.cssource/code/snippets/2darrays.cs renamed to source/code/projects/2DarrayExercise/2DarrayExercise/Program.cs source/code/snippets/2darrays.cs renamed to source/code/projects/2DarrayExercise/2DarrayExercise/Program.cs

@@ -5,17 +5,33 @@ class Program
   static void Main()
   {
     // Example array1
-    int[,] matrix =
+    int[,] matrix1 =
     {
       { 1, 2, 3 },
       { 4, 5, 6 },
       { 7, 8, 9 },
       { 10, 11, 12 },
     };
     // End of example array1
-    Display(matrix);
-    Rotate(ref matrix);
-    Display(matrix);
+    Console.WriteLine("Example 1:");
+    Display(matrix1);
+    Console.WriteLine("We now rotate the array.");
+    Rotate(ref matrix1);
+    Display(matrix1);
+    
+    // Example array2
+    int[,] matrix2 =
+    {
+      { 1, 2, 3, 4 },
+      { 5, 6, 7, 8 },
+      { 9, 10, 11, 12 }
+    };
+    // End of example array2
+    Console.WriteLine("Example 2:");
+    Display(matrix2);
+    Console.WriteLine("We now rotate the array.");
+    Rotate(ref matrix2);
+    Display(matrix2);
   }
 
   // Method to display 2-d arrays
@@ -47,8 +63,10 @@ static void Rotate(ref int[,] matP)
       for (int col = 0; col < tmp.GetLength(1); col++)
       {
         tmp[row, col] = matP[
-          tmp.GetLength(1) - col - 1,
-          row
+          // This would be incorrect:
+          // tmp.GetLength(0) - col, row 
+          // can you figure out why?
+          tmp.GetLength(1) - col - 1, row
         ];
       }
     }

source/lectures/data/manipulating_rectangular_arrays.md

@@ -13,7 +13,7 @@ The code for this lecture is available [in this archive](./code/projects/MagicSq
 
 The following code sum the values contained in a 2-dimensional array row per row, and display the result each time before moving on to the next row:
 
-```
+```{download="./code/projects/MagicSquare.zip"}
 !include`snippetStart="// Summing the values row per row", snippetEnd="As an exercise, you can"` code/projects/MagicSquare/MagicSquare/Program.cs
 ```
 
@@ -25,7 +25,7 @@ A [magic square](https://en.wikipedia.org/wiki/Magic_square) is a square matrix
 
 The following is an example of a magic square:
 
-```
+```{download="./code/projects/MagicSquare.zip"}
 !include`snippetStart="// Examples courtesy of https://en.wikipedia.org/wiki/Magic_square", snippetEnd="// Check by hand that this square is indeed magic!"` code/projects/MagicSquare/MagicSquare/Program.cs
 ```
 
@@ -47,7 +47,7 @@ $$2+7+6=15$$
 
 A method to return `true` if the 2d-matrix of `int` passed as an argument is a magic square is as follows:
 
-```
+```{download="./code/projects/MagicSquare.zip"}
 !include code/projects/MagicSquare/MagicSquare/MagicSquare.cs
 ```
 

source/solutions/data/2darrays.md

@@ -116,8 +116,8 @@ tags:
 #. Write a `Display` static method that takes as an argument a 2-dimensional array and displays it at the screen.
 
     <details>
-    <summary>Solution</summary>```
-    !include`snippetStart="// Method to display 2-d arrays", snippetEnd="// End of method to display 2-d arrays"` code/snippets/2darrays.cs
+    <summary>Solution</summary>```{download="./code/projects/2DarrayExercise.zip"}
+    !include`snippetStart="// Method to display 2-d arrays", snippetEnd="// End of method to display 2-d arrays"` code/projects/2DarrayExercise/2DarrayExercise/Program.cs
     ```
     </details>
 
@@ -183,7 +183,7 @@ tags:
 #. Write a program that "rotate" a 2-dimensional array 90° clockwise. For example, the array 
 
     ```
-    !include`snippetStart="// Example array1", snippetEnd="// End of example array1"` code/snippets/2darrays.cs
+    !include`snippetStart="// Example array1", snippetEnd="// End of example array1"` code/projects/2DarrayExercise/2DarrayExercise/Program.cs
     ```
 
     would become
@@ -195,8 +195,8 @@ tags:
     ```
 
     <details>
-    <summary>Solution</summary>```
-    !include`snippetStart="// Method to rotate an array 90° clockwise", snippetEnd="// End of method to rotate an array 90° clockwise"` code/snippets/2darrays.cs
+    <summary>Solution</summary>```{download="./code/projects/2DarrayExercise.zip"}
+    !include`snippetStart="// Method to rotate an array 90° clockwise", snippetEnd="// End of method to rotate an array 90° clockwise"` code/projects/2DarrayExercise/2DarrayExercise/Program.cs
     ```
     </details>