IntToStr and StrToInt are nice functions, but if you are dealing with other number systems then binarie, decimal or sedecimal you have to do this by yourself. Here is a solution for this.

The following two functions convert numbers to strings and back again. The number can be converted to any numeric base between 2 and 36. 2 because thats the minimum base (binary) and 36 because otherwise we´re out of numbers - 0..9 and A..Z used for representing numbers.

This one converts a number to its string representation:

```const MinBase = 2;
MaxBase = 36;

function NumToStr (num, len, base: Integer;                   neg: Boolean; fill: char): string;
// num = the number to convert
// len = minimum length of the resulting string
// base = numeric base
//        2 = bin, 8 = octal, 10 = dec, 16 = hex
// neg = if true num is treated as negativ
// fill = character that ist used as fill in
// to get a string of the ‘length’ len
//
// Example:
// NumToStr (45, 8, 2, false, ‘0′) > ‘00101101′
// NumToStr (45, 4, 8, false, ‘0′) > ‘0055′
// NumToStr (45, 4, 10, false, ‘ ‘) > ‘ 45′
// NumToStr (45, 4, 16, false, ‘0′) > ‘002D’
// NumToStr (45, 0, 36, false, ‘ ‘) > ‘19′
//
var s: string;
digit: Integer;
begin
num:= ABS (num);
if ((base >= MinBase) and
(base <= MaxBase)) then begin
s:= '';
repeat
digit:= num mod base;
if digit < 10 then
Insert (CHR (digit + 48), s, 1)
else
Insert (CHR (digit + 55), s, 1);
num:= num div base;
until num = 0;
if neg then Insert ('-', s, 1);
while Length(s) < len do Insert (fill, s, 1);
end;
Result:= s;
end;
```
This is the counterpart to the function above. It converts a string containing an number into its numerical value:
```function StrToNum (const s: string; base: Integer;
neg: Boolean; max: Integer): Integer;
// s = the string containing the number
// base = numeric base that is expected
// neg = string can contain ‘-’ to show if < 0
// max = maximum number that can be contained
//
// Example:
// i:= StrToNum ('00101101', 2, false, MaxInt);
// i:= StrToNum ('002D', 16, false, MaxInt);
// i:= StrToNum ('-45', 10, true, MaxInt);
// i:= StrToNum ('ZZ', 36, true, MaxInt);
//
var negate, done: Boolean;
i, ind, len, digit, mmb: Integer;
c: Char;
mdb, res: Integer;
begin
res:= 0; i:= 1; digit:= 0;
if (base >= MinBase) and
(base <= MaxBase) then begin
mmb:= max mod base;
mdb:= max div base;
len:= Length (s);
negate:= False;
while (i <= len) and (s[i] = '') do Inc (i);
if neg then begin
case s[i] of
'+': Inc (i);
'-': begin Inc (i); negate:= TRUE; end;
end; (* CASE *)
end; (* IF neg *)
done:= len > i;
while (i <= len) and done do begin
c:= Upcase (s[i]);
case c of
'0'..'9': digit:= ORD(c) - 48;
'A'..'Z': digit:= ORD(c) - 55;
else done:= FALSE
end; (* CASE *)
done:= done and (digit < base);
if done then begin
done:= (res < mdb) or ((res = mdb) and
(digit <= mmb));
if done then begin
res:= res * base + digit;
Inc (i);
end; (* IF done *)
end; (* IF done *)
end; (* WHILE *)
if negate then res:= - res;
end; (* IF done *)
Result:= res;
end;
```