Variable "q" does not seem to be initialized
Variable "x" does not seem to be initialized

var a:array of integer;w,x,c:string;q,u,n,i:integer;
begin
read(n);setlength(a,n);
w:='10';c:='1';
for i:=0 to n-1 do
begin
read(a[i]);
if q<a[i] then q:=a[i];
end;
while length(c)<=q do
begin
str(w,x);
c:=c+x;
w:=w+'0';
end;
for i:=0 to n-1 do
begin
u:=a[i];
write(c[u],' ')
end;
end.

You didn't initialize 'q' and 'x'.
There no 'q:=' or 'x:=' in the code