title: Wanting to truncate address for clarity not working as expected
body: <p>Wanting to truncate addresses for clarity.
  Not looking for improved code, 
  just why the hex code subtraction does't seem to work properly.</p>
  
  <p>First result with 'zero' being subtracted from 'cname' and 'arptr':</p>
  
  <pre><code>address of 'cname' is 0x7fff5fbff720
  and of 'arptr' is     0x7fff5fbff720
  </code></pre>
  
  <p>Wanting to truncate unneeded digits for clarity
  I subtract 0x7fff5fbf0000 thinking I'll get
  0x00000000f720, but:</p>
  
  <p>Second result with 'trunker' being subtracted from 'cname' and 'arptr':</p>
  
  <pre><code>address of 'cname' is 0xffff00014082f720
  and of 'arptr' is     0xffff00014082f720
  </code></pre>
  
  
  
  <pre><code>#include &lt;stdio.h&gt;
  #define trunker 0x7fff5fbf0000
  #define zero    0x000000000000
  
  int main(void) {
  
      char cname[3][3] = {'a','b','c','e','f','g','i','j','k'};
      char (* arptr)[3];
  
      arptr = cname;
  
      printf("address of cname is %p\nand of arptr is     %p\n",
      cname-zero,arptr-zero);   //replace zero with trunker 
                                //to truncate first 8 digits
  
      return 0;
  
  }
  </code></pre>
  
  <p>Using Xcode on OS X</p>
  
  <p>Thanks and Happy New Year 2012</p>