Category : Pascal Source Code
Archive   : VCARD.ZIP
Filename : VERICARD.PAS

Unit Vericard;


{$F+,D+,L+}



Interface


Function Vc(c : string) : char;


Implementation



Function Vc(C : String) : Char;
var
card : string[21];
Vcard : array[0..21] of byte absolute card;
Xcard : Integer;
Cstr : String[21];
y,x : integer;


Begin

x:=0;

Cstr:=' ';

Cstr:='';

Fillchar(Vcard,22,#0);

Card:=C;

for x:=1 to 20 do if Vcard[x] IN ([48..57]) then Cstr:=Cstr+chr(Vcard[x]);

Card:='';

Card:=Cstr;

Xcard:=0;

if NOT odd(length(card)) then

for x:=length(card)-1 downto 1 do
begin
if odd(x) then y:=((Vcard[x]-48)*2) else y:=(Vcard[x]-48);
if y>=10 then y:=((y-10)+1);
Xcard:=(Xcard+y);
end else for x:=length(card)-1 downto 1 do
begin
if odd(x) then y:=(Vcard[x]-48) else y:=((Vcard[x]-48)*2);
if y>=10 then y:=((y-10)+1);
Xcard:=(Xcard+y);
end;

x:=(10-(Xcard MOD 10));

if (x=10) then x:=0;

if x=(Vcard[length(card)]-48) then Vc:=Cstr[1] else Vc:=#0;

end;

end.