PROGRAM COMPARE;(*$I+,S+  *)
(* THIS PROGRAM WILL DO A BYTE BY BYTE COMPARE
 OF TWO FILES. UPON EXECUTION THE OPERATOR WILL
 BE ASKED THE NAME OF THE TWO INPUT FILES TO BE
 COMPARED AND THE NAME OF THE OUTPUT FILE THAT THE COMPARE INFO
 IS TO BE DUMPED TO. *)
CONST
 BLANK14='              ';
TYPE
 BYTE=0..255;
 STR4=STRING 4;
 STR16=ARRAY[1..16] OF CHAR;
VAR
 NOCOMPARE: BOOLEAN;
 ABYTE1,ABYTE2: BYTE;
 FVAR1,FVAR2: FILE OF BYTE;
 FVAR3: TEXT;
 HEXSTRING: STR16;
 FNAME1,FNAME2,FNAME3: STRING 14;
 K: INTEGER;
 I: REAL;
(****************************************************************)
PROCEDURE CNVRTTOHEX(INT: INTEGER;VAR HEXVAL: STR4);
 CONST
  HEX1000=4096;
 VAR
  K,DIVISOR,J: INTEGER;
 BEGIN
  HEXVAL:='    ';
  DIVISOR:=HEX1000;
  FOR K:=1 TO 4 DO
   BEGIN
    J:=INT DIV DIVISOR;
    INT:=INT MOD DIVISOR;
    HEXVAL[K]:=HEXSTRING[J+1];
    DIVISOR:=DIVISOR DIV 16;
   END;
 END;
(****************************************************************)
 PROCEDURE LOGDIFF;
  VAR
   T1:STR4;
   TEMPINT: INTEGER;
  BEGIN
   WRITE(FVAR3,I:5:0,'  ');
   TEMPINT:=ABYTE1;
   CNVRTTOHEX(TEMPINT,T1);
   WRITE(FVAR3,T1[3],T1[4],'  ');
   TEMPINT:=ABYTE2;
   CNVRTTOHEX(TEMPINT,T1);
   WRITELN(FVAR3,T1[3],T1[4]);
  END;
(****************************************************************)
BEGIN
 HEXSTRING:='0123456789ABCDEF';
 NOCOMPARE:=FALSE;
 FNAME1:=BLANK14;
 FNAME2:=BLANK14;
 FNAME3:=BLANK14;
 WRITE('ENTER COMPARE FILE NUMBER 1-- ');
 READLN(FNAME1);
 WRITE('ENTER COMPARE FILE NUMBER 2-- ');
 READLN(FNAME2);
 WRITE('ENTER OUTPUT LOG FILE-- ');
 READLN(FNAME3);
 RESET(FNAME1,FVAR1);
 RESET(FNAME2,FVAR2);
 REWRITE(FNAME3,FVAR3);
 I:=1;
 WRITELN(FVAR3,'COMPARING ',FNAME1,' WITH ',FNAME2);
 WRITELN('COMPARING ',FNAME1,' WITH ',FNAME2);
 WRITELN('VERSION 0.0 ,2/22/81 OF COMPARE PROGRAM');
 WHILE ((NOT EOF(FVAR1)) AND (NOT EOF(FVAR2))) DO
  BEGIN
   READ(FVAR1,ABYTE1);
   READ(FVAR2,ABYTE2);
   IF ABYTE1<>ABYTE2
    THEN
     BEGIN
      LOGDIFF;
      NOCOMPARE:=TRUE;
     END;
   I:=I+1;
   END;
 IF (EOF(FVAR1) AND (NOT EOF(FVAR2)))
  THEN
   BEGIN
    WRITELN(FVAR3,FNAME2,' IS LONGER THAN ',FNAME1);
    NOCOMPARE:=TRUE;
   END;
 IF ((NOT EOF(FVAR1)) AND EOF(FVAR2))
  THEN
   BEGIN
    WRITELN(FVAR3,FNAME1,' IS LONGER THAN ',FNAME2);
    NOCOMPARE:=TRUE;
   END;
 IF NOT NOCOMPARE
  THEN
   WRITELN(FVAR3,' BOTH FILES COMPARED COMPLETELY WITH EACH OTHER');
 WRITELN(FVAR3,' THERE WERE ',(I-1):2:0,' CHARACTERS READ');
 END.

.