Edit variable-length array example

The current example seems to be trying to set a size for a char buffer,
use fgets to populate that buffer, and then use strtoul to convert the
char content to an unsigned integer. However, this doesn't work as
intended (in fact, it results in printing "sizeof array = 0"), and so
adapt to a simpler fscanf example. Also remove some ambiguous language
in the example output.

c.html.markdown

@@ -148,15 +148,10 @@ int main (int argc, char** argv)
   printf("Enter the array size: "); // ask the user for an array size
   int size;
   fscanf(stdin, "%d", &size);
-  char buf[size];
+  int var_length_array[size]; // declare the VLA
-  fgets(buf, sizeof buf, stdin);
-
-  // strtoul parses a string to an unsigned integer
-  size_t size2 = strtoul(buf, NULL, 10);
-  int var_length_array[size2]; // declare the VLA
   printf("sizeof array = %zu\n", sizeof var_length_array);
 
-  // A possible outcome of this program may be:
+  // Example:
   // > Enter the array size: 10
   // > sizeof array = 40