move exercises and lectures into subfolders

Exercises/C15/pointer_array_example_1.c

@@ -0,0 +1,20 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+
+    // Declare and populate an integer array
+    int MyArray[10] = {2,4,6,8,10,12,14,18,20};
+    
+    // Declate an integer pointer
+    int *pI;
+
+    // Get the start address  by asking for the address iof array item [0]
+    pI = &MyArray[0];
+
+    // Or, use the fact the array name on its own is the start address of the array
+    pI = MyArray;
+
+    return 0;   // Exit
+}

Exercises/C15/pointer_array_example_2.c

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+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    // Declare an integer array and an integer pointer
+    int MyArray[10] = {2,4,6,8,10,12,14,16,18,20};
+    int *pI;
+
+    // Get the start address  by asking for the address iof array item [0]
+    pI = &MyArray[0];   // Or use:     pI = MyArray;
+
+    // Display the 1st item in the array, first be accessing rhe array
+    printf("The value at array item [0] is %d\n", MyArray[0]);
+
+    // Since the pointer points to the address of the 1st item we can
+    // access it as we would for a pointer pointing to any single variable
+    
+    printf("The value at the memory address held in pI is %d\n", *pI);
+
+    return 0;   // Exit
+}

Exercises/C15/pointer_array_example_3.c

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+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+
+    // Declare an integer array and an integer pointer
+    int MyArray[10] = {2,4,6,8,10,12,14,16,18,20};
+    int *pI;
+    int i;
+
+    // Get the start address  by asking for the address iof array item [0]
+    pI = &MyArray[0];       // or use: pI = MyArray;
+
+    // Use loop to display values
+    for ( i = 0 ; i < 10 ; i++ )
+    {
+        printf ("Value at index %d (direct access to the arrays) is: %d\n", i, MyArray[i]);
+        printf ("Value at index %d (access via the pointer) is: %d\n", i, pI[i]);
+    }
+
+    return 0;   // Exit
+}

Exercises/C15/pointer_array_example_4.c

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+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    // Declare an integer array and an integer pointer
+    int MyArray[10];
+    int *pI;
+    int i;
+
+    // Get the start address  by asking for the address iof array item [0]
+    pI = &MyArray[0];       // or use: pI = MyArray;
+
+    // Use loop to display values
+    for ( i = 0 ; i < 10 ; i++ )
+    {
+        //  Set the value then use the increment operator to move the pointer
+        //  to the next memory location. you can picture this as two steps: '
+        //
+        //      *pI = 5 + 4*i;
+        //  then
+        //      *pI++;
+
+        *pI++ = 5 + 4*i;	// set value at index[i] to 5+4*i
+    }
+
+	// Display the values placed in the array
+    for ( i = 0 ; i < 10 ; i++)
+    {
+        printf("%d ", MyArray[i]);
+    }
+    return 0;   // Exit
+}