Textfile Input and Output  133  program PromptExample(Input,Output);  var Guess:  Integer;  begin  {  Implicit Reset (Input)  occurs here.  }  Writeln('Please enter an integer from 1  and 10.');  Read(Guess)  1.Read(Vl, ... ,Vn)  stands for  Read(Input,Vl, ... ,Vn)  2. Read(F,Vl, ... ,Vn)  stands for  begin Read(F,Vl); ... ;Read(F,Vn)  end  3. Readln(Vl, ... ,Vn)  stands for  Readln(Input,Vl, ... ,Vn)  4. Readln(F,Vl, ... ,Vn)  stands for  begin Read(F,Vl); ... ;Read(F,Vn);  Readln(F)  end  The effect for Readln  is that after Vn  is read (from F), the  remainder of the current line is skipped. (However, the values  of Vl ... Vn  may stretch over several lines.)  Let Vl,V2, ... ,Vn  denote variables of type Char, Integer, (or sub­ range of either) or  Real, and let F denote a textfile. Read (F, V)  is an  error if  F is undefined or F is not in inspection mode or eof (F)  is true.  The procedure Read was defined for textfiles in Section 9.B. Read is  extended not only to accept a variable number of parameters, but also to  accept parameters of type  Integer  (or a subrange of Integer) and  Real.  A Pascal implementation  not  employing the delayed evaluation of  Input  i  will cause a request or wait for data before the message is  written because of the implicit  Reset (Input)  which occurs as the  program begins executing.  Whether or not delayed evaluation is  supported is implementation-defined.  12.B.  The Procedures Read and Readln 