//This is a lexically, syntactically, and semantically
//valid DJ program.  However, an error occurs during
//execution because we try to select a field/method 
//of a null (i.e., unallocated) object.
//This is called a null-dereference error because we
//are attempting to dereference, or get the value of, 
//a variable whose object-value is null (i.e., 0).

//During execution, this program produces no output.
//Instead it halts after a null-dereference check fails.

class C extends Object {nat n;}
main {
  C c;
  printNat(c.n);
  printNat(8);
}