Predeclared Procedures and Functions  207  Sqr(x)  an arithmetic function that computes the real value x  *  x  if x  is real or the  integer value x  *  x  if x  is integer.  It  is an error if that value does not exist.  Sqrt(x)  an arithmetic function that computes the real, non-negative square root of the in­ tegerorrealparameterx  wherex  >=  o.  Sqrt (x)  isanerrorifx  <  o.  Succ(x)  an ordinal function that returns the next ordinal value (successor) after the ordinal  parameter x, if such a successor exists: ord (succ (x))  =  ord (x)  +  l.  Sue c (x)  is an error if x  is the largest value of its type.  Trunc(r)  a transfer function that computes the greatest integer less than or equal to the real  parameter r  for r  >=  0.0, or the least integer greater than or equal to the real  parameter r, for r  < o. 0 if such a value exists in the type Integer. Otherwise it is an  error.  Unpack(p,u,i)  a data-transfer function that unpacks the packed array p  into the non-packed  array u  starting at element i  in the non-packed array.  Write(f,v)  See User Manual, Chapters 9 and 12, and Report Sections 11.4 and 12.3.  See User Manual, Chapters 9 and 12, and Report Sections 11.4 and 12.3.  Write(f,vl, .. ,vn)  Writeln  See User Manual, Chapters 9 and 12, and Report Section 12.4.  See User Manual, Chapters 9 and 12, and Report Section 12.4.  Writeln(f,el, ... ,en) 