title: delete partial memory of the pointer
body: <p>Is there any way i can delete the partial memory of the pointer.?
  for example </p>
  
  <pre><code>char *c = new char[1000];
  sprintf(c,"this is it");
  </code></pre>
  
  <p>As it can be seen a lot of memory is getting wasted here. can I free the memory more than the required.?</p>