Algorithm Math Delphi

Title: Convert octal to binary
Use OctToBin function to convert number in octal format to binary format.
function OctToBin(OctStr: string): string;
function DecToBinStr(N: Integer): string;
var
S: string;
i: Integer;
begin
if N0 then
for i:=1 to SizeOf(N)*8 do
begin
if N1) do
Delete(Result, 1, 1);
end;
end;