hex_to_bin

program hex_to_bin;               {lielais no mazā atšķiras pa 32 vietām}
var h,b: string;
var i,n: integer;
var d: longint;
label back;

function hextodec(x:string):longint;
var l,s: longint;
var n,g: integer;
begin
l:=0;
s:=1;
for g:= length(x) downto 1 do
        begin
        l:=l+(ord(x[g])-48)*s;
        s:=s*16;
        end;
hextodec:=l;
end;

function dectobin(x:longint):string;
var b,e,f: longint;
var c: string;
begin
b:=0;
f:=0;
while not x<=0 do
begin
inc(b);
e:=( x mod 2)+48;
c[b]:=chr(e);
x:= x div 2;
if(x=0) then break;
end;
for e:= b downto 1 do
begin
write(c[e]);
end;
dectobin:=c;
end;



begin
back:writeln('ievadiet heksidecimālu skaitli- ');
readln(h);
for i:= 1 to length(h) do
begin
if (ord(h[i])>57) and (ord(h[i])<65) then goto back;
if (ord(h[i])>96) and (ord(h[i])<103) then h[i]:=chr(ord(h[i])-32);
if (ord(h[i])>64) and (ord(h[i])<71)
then h[i]:=chr(ord(h[i])-7);
if ((ord(h[i])>47) and (ord(h[i])<65)) then else goto back; end;

d:=hextodec(h);
h:=dectobin(d);
readln;
end.