program Ascii_Table;

uses crt;


procedure writexy(text : string;
                   row : byte;
                colour : byte);

var
   len    : byte;
   column : byte;

begin
   len := length(text);
   column := 40-(len div 2);
   gotoxy(column,row);
   textcolor(colour);
   write(text);
   gotoxy(1,25);
end;


procedure help_page;

var
   pause : char;

begin
   textcolor(black);
   clrscr;

   writexy('Ascii Table v1.1',8,4);
   writexy('Programmed by Fraser King',9,4);

   writexy('To display a character in the Ascii Table. Simply',12,6);
   writexy('run the Ascii program and look up the character you',13,6);
   writexy('want. Then remember the code for that character.',14,6);
   writexy('At the command prompt hold down ALT and using',15,6);
   writexy('the numeric keypad type in the Ascii code.',16,6);

   writexy('Example.  ALT + 65 displays the character A',19,4);

   pause := readkey;

   textcolor(lightgray);
   clrscr;
   halt;
end;


procedure display_ascii_table;

var
   x,y     : byte;
   i       : integer;
   counter : byte;
   row     : byte;
   ok      : boolean;

begin
   textcolor(black);
   clrscr;

   writexy('Ascii Table',1,2);
   writexy('Type at command prompt',24,2);
   writexy('Ascii /? for help page',25,2);

   row := 19;
   ok := FALSE;
   x := 1; y := 3;
   counter := 0;

   repeat
      for i := counter to counter + row do
      begin
         gotoxy(x,y);
         textcolor(7);
         write(i:4,' ');
         textcolor(2);
         write(chr(i):1);
         if i = 255 then
         begin
            ok := TRUE;
            i := i + 4;
         end;
         y := y + 1;
      end;
      y := 3; x := x + 6;
      counter := counter + 20;
   until ok;
end;


{  Start of main program   }


var
   pause : char;

begin
   textmode(80);

   if paramstr(1) = '/?' then help_page;

   display_ascii_table;
   pause := readkey;

   textcolor(lightgray);
   clrscr;
end.


{   End of main program   }