How can I extract a substring?

I have function in delphi

function GetHardDiskSerial(const DriveLetter: Char): string; var NotUsed: DWORD; VolumeFlags: DWORD; VolumeInfo: array[0..MAX_PATH] of Char; VolumeSerialNumber: DWORD; begin GetVolumeInformation(PChar(DriveLetter + ':\'), nil, SizeOf(VolumeInfo), @VolumeSerialNumber, NotUsed, VolumeFlags, nil, 0); Result := Format('%8.8X', [VolumeSerialNumber]) end; 

how to take the output character to 2 up to 4.

Example: 7121334

• Result must be: 121

cSerial.text=......................................

1 Answer

You can use the Copy function to extract a sequence of characters from a string:

cSerial.Text := Copy(Result, 2, 3); 

Note that the third parameter is the number of characters to extract, not the index of the last character.