program sujet4;
uses wincrt;
var ch:string;
procedure saisie(var ch:string);
begin repeat
write('Donner un code ');
readln(ch);
until length(ch)=13;
end;
function verif(ch:string):boolean;
var
s,i,x,e,p,reste:integer;
begin s:=0;
for i:= 1 to length(ch)-1 do begin
val(ch[i],x,e);
if (i mod 2=0) then x:=x*3;
s:=s+x;
end;
reste:=s mod 10;
p:=10-reste;
val(ch[length(ch)],x,e);
if x=p then verif:=true else verif:=false;
end;
begin saisie(ch);
if verif(ch) then write('Code EAN13') else write('Code non valide');
end.
