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From: cs202216@marmaduke.acslab.umbc.edu (cs202216)
Newsgroups: comp.lang.pascal
Subject: Re: "Dots will echo:" for passwords...
Message-ID: <1991Apr10.140340.7287@umbc3.umbc.edu>
Date: 10 Apr 91 14:03:40 GMT
References: <40822@netnews.upenn.edu>
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In article <40822@netnews.upenn.edu> garay@hyper.lap.upenn.edu (John Garay) writes:
>
>I'm interested in a procedure in TP which will echo dots to the screen instead
>of the actual keys pressed.  In other words, one of the ol'
>	'Please type in password (dots will echo):'
>types of things.  The form I have now (w/ the password broadcasted on the
>screen is: 	clrscr;
>		writeln ('Please Type Password:');
>		readln (password);
>
>I figure somewhere between the writeln and the readln there's got to be a way
>to make dots echo instead of the (secret) password.  Any ideas, anyone?
>A little background:  IBM TP3.01 (WAIT!  I'm interested in ideas with any
>TP version!).    Thanks much for the help....
>******************************************************************************
>
>    John Garay            e-mail  :  garay@hyper.lap.upenn.edu
>		          Office phone :  (215)  898-1954
>			  Home Phone   : (215)  382-4102
>			  Donations    :  4034 Walnut, Philly, PA   19104
>
>"Change the Way People think, and things will Never be the Same."  S. Biko
>
>******************************************************************************
>
>	

	To do this, you'll have to write a procedure to replace the readln
procedure.

example:

	Procedure GetPassword(var s : string);
	const
		bs  = #8;
		cr  = #13;
		esc = #27;
		bell = #7;
	var
		ch : char;
	begin
	s:='';
	repeat
	if keypressed then
		begin
		ch:=readkey;
		case ch of
			bs : begin
				if length(s) > 0 then
					begin
					delete(s,length(s),1);
					write(bs+' '+bs);
					end
				else
					write(bell);
			     end;
			cr : begin
			     end;
		        esc : begin
				{ If escape is pressed, clear the input }
				while length(s) > 0 do
				   begin
				   write(bs+' '+bs);
				   delete(s,length(s),1);
				   end;
			      end;
			else
				begin
				s:=s+ch;
				write('.');
				end;
			end;

	until ch = cr;
	writeln;
	end;


Hope this helps.


Matt Gove
Internet: cs202216@umbc5.umbc.edu