[SPCA] Finish pointers section

semester3/spca/code-examples/00_c/00_basics/05_pointers.c

@@ -1,6 +1,12 @@
+#include "01_func.h" // See a few pages up for declarations
+#include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 
+void a_function( int ( *func )( char * ), char prompt[] ) {
+    ( *func )( prompt ); // Call function with arguments
+}
+
 int main( int argc, char *argv[] ) {
     int x = 0;
     int *p = &x;          // Get x's memory address
@@ -11,8 +17,7 @@ int main( int argc, char *argv[] ) {
     int *null_p = NULL;   // Create NULL pointer
     *null_p = 1;          // Segmentation fault due to null pointer dereference
 
-    // ── pointer arithmetic ───────────────────────────────────────────
-    // Already seen a bit in the c arrays section
+    // pointer arithmetic
     int arr[ 3 ] = { 2, 3, 4 };
     char c_arr[ 3 ] = { 'A', 'B', 'C' };
     int *arr_p = &arr[ 1 ];
@@ -22,6 +27,11 @@ int main( int argc, char *argv[] ) {
 
     char *arr_p_c = (char *) arr_p; // Cast to char pointer (points to first byte of arr[0])
     printf( "%d", *( arr_p - 5 ) ); // No boundary checks (can access any memory)
+    assert( arr == &( arr[ 0 ] ) ); // Evaluates to true
+    int new_arr[ 3 ] = arr;         // Compile time error (cannot use other array as initializer)
+    int *new_arr_p = &arr[ 0 ];     // This works
+
+    a_function( &get_user_input_int, c_arr );
 
     return EXIT_SUCCESS;
 }