ໃນພາສາ Delphi ມີ ປະເພດຂໍ້ມູນຫລາກຫລາຍຄືກັບພາສາໂປຣແກຣມອື່ນໆ
ຕົວຢ່າງ ການປະກາດຕົວປ່ຽນ
var // This starts a section of variables LineTotal : Integer; // This defines an Integer variable called LineTotal First,Second : String; // This defines two variables to hold strings of text
ຈາກໂຄດຂ້າງເທິງ ເຫັນວ່າ ການເລີ່ມຕົ້ນດ້ວຍຊື່ຕົວປ່ຽນ ແລ້ວຕາມດ້ວຍ ປະເພດຂໍ້ມູນຕົວປ່ຽນ ສຶ່ງສຳຄັນ ຊື່ຂອງຕົວປ່ຽນຕ້ອງແມ່ນບໍ່ຊ້ຳກັນ ແລະ ການປະກາດຕົວປ່ຽນ ຈະບໍ່ຈຳແນກ ຕົວອັກສອນ ໃຫຍ່ ຫລື ນ້ອຍ
ຂໍ້ມູນປະເພດຕົວເລກ
Var // Integer data types : Int1 : Byte; // 0 to 255 Int2 : ShortInt; // -127 to 127 Int3 : Word; // 0 to 65,535 Int4 : SmallInt; // -32,768 to 32,767 Int5 : LongWord; // 0 to 4,294,967,295 Int6 : Cardinal; // 0 to 4,294,967,295 Int7 : LongInt; // -2,147,483,648 to 2,147,483,647 Int8 : Integer; // -2,147,483,648 to 2,147,483,647 Int9 : Int64; // -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 // Decimal data types : Dec1 : Single; // 7 significant digits, exponent -38 to +38 Dec2 : Currency; // 50+ significant digits, fixed 4 decimal places Dec3 : Double; // 15 significant digits, exponent -308 to +308 Dec4 : Extended; // 19 significant digits, exponent -4932 to +4932
ຂໍ້ມູນປະເພດຂໍ້ຄວາມອັກສອນ
var Str1 : Char; // Holds a single character, small alphabet Str2 : WideChar; // Holds a single character, International alphabet Str3 : AnsiChar; // Holds a single character, small alphabet Str4 : ShortString; // Holds a string of up to 255 Char's Str5 : String; // Holds strings of Char's of any size desired Str6 : AnsiString; // Holds strings of AnsiChar's any size desired Str7 : WideString; // Holds strings of WideChar's of any size desired
ຂໍ້ມູນປະເພດ Logica
var Log1 : Boolean; // Can be 'True' or 'False'
ປະກາດຕົວປ່ຽນ
ຂໍ້ມູນປະເພດ Sets, enumerations and subtypes
type TSuit = (Hearts, Diamonds, Clubs, Spades); // Defines the enumeration var suit : TSuit;
type TWeek = Set of 1..7; // Set comprising the days of the week, by number var week : TWeek; begin week := [1,2,3,4,5]; // Switch on the first 5 days of the week end;
ຕົວຢ່າງ ການກຳນົດຄ່າຈາກຕົວປ່ຽນ
types TWeek = 1..7; // Set comprising the days of the week, by number TSuit = (Hearts, Diamonds, Clubs, Spades); // Defines an enumeration const FRED = 'Fred'; // String constant YOUNG_AGE = 23; // Integer constant TALL : Single = 196.9; // Decimal constant NO = False; // Boolean constant var FirstName, SecondName : String; // String variables Age : Byte; // Integer variable Height : Single; // Decimal variable IsTall : Boolean; // Boolean variable OtherName : String; // String variable Week : TWeek; // A set variable Suit : TSuit; // An enumeration variable begin // Begin starts a block of code statements FirstName := FRED; // Assign from predefined constant SecondName := 'Bloggs'; // Assign from a literal constant Age := YOUNG_AGE; // Assign from predefined constant Age := 55; // Assign from constant - overrides YOUNG_AGE Height := TALL - 5.5; // Assign from a mix of constants IsTall := NO; // Assign from predefined constant OtherName := FirstName; // Assign from another variable Week := [1,2,3,4,5]; // Switch on the first 5 days of the week Suit := Diamonds; // Assign to an enumerated variable end; // End finishes a block of code statements
FirstName is now set to 'Fred' SecondName is now set to 'Bloggs' Age is now set to 55 Height is now set to 191.4 IsTall is now set to False OtherName is now set to 'Fred' Week is now set to 1,2,3,4,5 Suit is now set to Diamonds (Notice no quotes)
ແບບ Arrays
var Suits : array[1..4] of String; // A list of 4 playing card suit names begin Suits[1] := 'Hearts'; // Assigning to array index 1 Suits[2] := 'Diamonds'; // Assigning to array index 2 Suits[3] := 'Clubs'; // Assigning to array index 3 Suits[4] := 'Spades'; // Assigning to array index 4 end;
ແບບ Records
type TCustomer Record firstName : string[20]; lastName : string[20]; age : byte; end;
var customer : TCustomer; // Our customer variable begin customer.firstName := 'Fred'; // Assigning to the customer record customer.lastName := 'Bloggs'; customer.age := 55; end;
customer.firstName is now set to 'Fred' customer.lastName is now set to 'Bloggs' customer.age is now set to 55
ປະເພດຂໍ້ມູນອື່ນໆ
ເປັນ object types:
Files
File variables represent computer disk files. You can read from and write to these files using file access routines. This is a complex topic covered in Files.
Pointers
Pointers are also the subject of an advanced topic - see Pointer reference. They allow variables to be indirectly referenced.
Variants
Variants are also an advanced topic - see Variant. They allow the normal Delphi rigid type handling to be avoided. Use with care!