Delphi basic knowledge Summary

☆Delphi Basic Data Type

Category				Range	Bytes	Remarks
Simple Type	Ordinal number	Integer	Integer	-2147483648 .. 2147483647	4	Signed 32-bit
			Cardinal	0... 4294967295	4	Unsigned 32-bit
			Shortint	-128 .. 127	1	8-digit signed
			Smallint	-32768 .. 32767	2	Signed 16-bit
			Longint	-2147483648 .. 2147483647	4	Signed 32-bit
			Int64	-263 .. 263	8	Signed 64-bit
			Byte	0... 255	1	Unsigned 8-bit
			Word	0... 65535	2	Unsigned 16-bit
			Longword	0... 4294967295	4	Unsigned 32-bit
		Character	Ansichar (char)	ANSI character set		8-digit
			Widechar	Unicode Character Set		16-bit
		Boolean	Boolean	False <true Ord (false) = 0 Ord (true) = 1 Succ (false) = true PRED (true) = false	1
			Bytebool	False <> true Ord (false) = 0 Ord (true) <> 0 Succ (false) = true PRED (false) = true	1
			Wordbool		2
			Longbool		4
		Real Number		Real	5.0x10-324 .. 1.7x10308	8	[Precision] 15 .. 16
				Real48	2.9 × 10-39 .. 1.7 × 1038	6	[Precision] 11 .. 12; Backward compatibility
	Single			1.5x10-45 .. 3.4x1038	4	[Precision] 7 .. 8
	Double			5.0x10-324 .. 1.7x10308	8	[Precision] 15 .. 16
	Extended			3.6x10-4951 .. 1.1x104932	10	[Precision] 19 .. 20
	Comp			-263 + 1 .. 263-1	8	[Precision] 19 .. 20
	Currency			-922337203685477.5808 .. 922337203685477.5807	8	[Precision] 19 .. 20
	String			Optional string	255 characters	2. 256b	Backward compatibility
				Ansistring	About 231 characters	4B .. 2 GB	8 (ANSI) characters
Widestring				About 230 characters	4B .. 2 GB	Multi-user service and Multi-language applications; Compatible with BSTR defined by com
Others				String String [0 .. 255] Pchar Pansistring Pwidestring
Structure Type	Set		Set	Up to 256 elements [0 .. 255]
	Array	Static Array
		Record		Record
	File		File
	Class		Class
	Class reference		Class reference
	Interface		Interface
	Pointer type	No type pointer		Pointer
Type pointer		Predefined type pointer	Pansistring Pstring Pbytearray Pcurrency Pdouble Pextended Psingle Pinteger Polevariant P1_string Ptextbuf Pvarrec Pvariant Pwidestring Pwordarray
Process type	Program process type		Procedural
	Object process type		Procedural
Variant Type			Variant
			Olevariant