Question

I have a random string of numbers
(numbers can only be used once, only from 1-9, almost any length(min 1,max 9)):

var
Input: String;
begin
Input := '431829576'; //User inputs random numbers

And now I need to get specified number to front. How about 5.

var
Number: Integer;
begin
Number := 5;

and function executes with result 543182976.

I don’t have any ideas how to make a function like this, Thanks.

Answer 1

Do you mean like this?

function ForceDigitInFront(const S: string; const Digit: Char): string;
begin
  result := Digit + StringReplace(S, Digit, '', []);
end;

A more lightweight solution is

function ForceDigitInFront(const S: string; const Digit: Char): string;
var
  i: Integer;
begin
  result := S;
  for i := 1 to Length(S) do
    if result[i] = Digit then
    begin
      Delete(result, i, 1);
      break;
    end;
  result := Digit + result;
end;