Перевод чисел с двоичной системы в десятичную

program p1;
uses crt;
var k,j,i,systema:integer;
n:longint;
a:array[1..23] of integer;
s:string[23];
sh:string[1];
q:string[1];
label m1,m2,m3,m4;
begin   clrscr;
m3: begin         I:=1;
writeln('vvedite 4islo:');
readln(n);
m2: begin
writeln('vvedite sistemu s4islenia:');
readln(systema);
case systema of
2: systema:=2;
8: systema:=8;
16: systema:=16;
else
writeln('vvedennaya sistema ne rasprostranena, vvedite druguyu');
goto m2;
end;     end;
 
m1:  begin
a[i]:=(n mod systema);
n:=(n div systema);
inc(i);
end;
if n>0 then goto m1;
k:=i-1;
write('Otvet: ');
for J:=k downto 1 do
begin case a[j] of
10: s[j]:='a';
11: s[j]:='b';
12: s[j]:='c';
13: s[j]:='d';
14: s[j]:='e';
15: s[j]:='f';
else
str(a[j],sh);
s[j]:=sh[1];
end;
write(s[j]);
end;
writeln;
writeln('rabota programmy zavershena, zhealaete vvesti eshe 4islo?>Y/N');
m4: begin
readln(q);
case q[1] of
'y': goto m3;
'n': exit;
else
writeln('otvet ne veren vvedite drugoi otvet:');
goto m4
end;
end;
end;
readln;
end.

program sdfa;
uses crt;
var S1,S2:string[15];
    i,m:integer;
begin clrscr;
write('Vvedite dvoi4ne 4islo -> ');
read(S1);
m:=0;
for i:=1 downto length(S1) do m:=m+S1[i]*(i-1);
str(m,S2);
writeln('Jomu vidpovida ',S2,' desatkove');
repeat until keypressed;
end.