ComputeFrequenciesString := proc(s::string)
   local T,i,c,l;
   T := table();
   l := length(s);
   for i from 1 to l do 
     c := s[i];
     if whattype(T[c])<>integer 
       then T[c] := 1; 
       else T[c] := T[c] + 1;
     end if;
   end do;
   i := indices(T);
   for c in i do
     T[op(c)] := 100*evalf(T[op(c)]/l);  
   end do;
   T
end proc;

ComputeFrequenciesNum := proc(a::integer)
   local T,i,c,l;
   T := table();
   i := a;
   l := 0; ### l = the number of two-digit blocks processed  
   while i>0 do
     c := i mod 100;
     if whattype(T[c])<>integer 
       then T[c] := 1; 
       else T[c] := T[c] + 1;
     end if;
     i := (i - c)/100;
     l := l + 1;
   end do;
   i := indices(T);
   for c in i do
     T[op(c)] := 100*evalf(T[op(c)]/l);  
   end do;
   T
end proc;

PrintFrequencies := proc(F::table)
  local clist;
  clist := sort([indices(F)], (a,b)->F[op(a)]>F[op(b)]); 
  map(c->printf("f%s = %2.2f%%\n", convert(c,string), F[op(c)]), clist)
end proc;

FileToString := proc(filename::string) 
  local s,line;
  s := ""; line := "";
  while line <> 0 do
    s := cat(s,line,"\n");
    line := readline(filename);
  end do;
  s
end proc;