Consider our String class: change the semantics for the assignment of strings so that two strings would share a common internal data buffer:

• Structure holding reference count and the buffer is moved to a nested class, StringReference
• References are managed by reassign
  • Takes ptr to a StringReference
  • If not NULL, reference to argument value is incremented
  • Reference to current value is decremented
  • If current reference is 0, object is deleted
  • Current object is set to refer to argument value