GENERAL TEXT FILE PROCESSING

Program File_IO;

Uses
  Crt;

Const
  Infilename = 'TEXTFILE.TXT';

Type
  Alphabet = Set of Char;

Var
  Ch: Char;
  Alpha: Alphabet;
  Total_chars, Total_alphabetic: Integer;
  Infile: Text;

Begin
  Clrscr;
  Alpha := ['A'..'Z','a'..'z'];
  Assign(Infile, Infilename);
  Reset(Infile);
  Textcolor(White);
  Writeln('Input file ', Infilename, ' opened for processing.');
  Total_chars := 0;
  Total_alphabetic := 0;

  While NOT EOF(Infile) Do
    Begin
      While NOT EOLN(Infile) Do
        Begin
          Read(Infile, Ch);
          Write(Ch);
          Total_chars := SUCC(Total_chars);
          If Ch in Alpha
            Then Total_alphabetic := SUCC(Total_alphabetic);
        End;
        Readln(Infile);
        Writeln;
    End;

  Close(Infile);
  Writeln('There were ', Total_chars, ' characters read in ', Infilename);
  Writeln('Of these, ', Total_alphabetic, ' were alphabetic.');
  Readln
End

INPUT FILE TEXTFILE.TXT:
a.bcde
fg.hij
klm.no
pqrs.t
u.vwxy
.....z


SCREEN OUTPUT FROM PROGRAM RUN:
Input file TEXTFILE.TXT opened for processing. 
a.bcde
fg.hij 
klm.no 
pqrs.t 
u.vwxy 
.....z 
There were 36 characters read in TEXTFILE.TXT 
Of these, 26 were alphabetic.