2.Data Type, Variables and Operators

2.Data Type Variables and Operators
2.1 Data Type
2.2 Constans
2.3 Variabels
2.4 Operators

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2.1 Data Type
Borland offers several types of data. we have to learn it, so it can be used properly and efficiently.there are several considerations to determine the Data type that we will use in the program.

• memory usage and data ranges

there are differences in the allocation of memory for one type of data with other data types. The best course uses data types according to our needs. example if we procces the data having ranges (0-100 )without decimals, then we used data type : Byte.(it is needed 1 Byte), compared if we use data type : word (2 byte ) or Integer (4 byte).but of course, if we processing the data over data type Byte( >100). we must not use data type :Byte.

• accuracy of calculation

although the memory savings is needed but we must having accuracy in calculation.so we must use the data type that having accuration in calculate.

there are data Type used in Borland

• 2.1.1 Integer
Integer used to specify the number with no decimal. there are integer tipe with range in memory used

Tipe	Ranges	Byte
Byte	0-255	1
Word	0-65535	2
ShortInt	-128-127	1
SmallInt	-32768 - 32767	2
Integer	-2147483648 - 147483647	4
Cardinal	0 - 2147483648	4
LongInt	2147483648 - 147483647	4

• 2.1.2
Used to declaretype of data that contains decimals

Type	Ranges	Byte
Real48	2.9 x 10-39 s.d 1.7 x 1038	6
Single	1.5 x 10-45 s.d 3.4 x 1038	4
Double	5.0 x 10-324 s.d 1.7 x 10308	8
Extended	3.6 x 10-4951 s.d 1.1 x 104932	10
Comp	-263+1 s.d 263-1	8
Currency	-922337203685477.5808 s.d 922337203685477.5807	8

real48 is used to maintain compatibility with previous versions of Delphi, extendedtype have a better accuracy but less in compatibility, currency type is best used to store fixed data are large, making it suitable to accommodate the value of currency and better in accuration
• 2.1.3 Boolean
it is used to declare logic data, thats TRUE and FALSE borland delphi have 4 boolean type :

Type	Byte
Boolean	1
ByteBool	1
WordBool	2
LongBool	4

• 2.1.4 Character
used to declare character 1 letter.borland have 3 Character Type:

Type	Byte	Fields
Char	1	1 ANSI Character
AnsiChar	1	1 ANSI Character
WideChar	2	1 Unicode Character

• 2.1.5 String
Used to declare more character example ; name, adress, code etc. borland have 3 string type:

Type	Byte	Max Fields
ShortString	2 s.d 256	256 Character
AnsiString	4 s.d 2 GB	231Character
WideString	4 s.d 2 GB	230 Character

ShortString its prevent the compability with other version of borland,AnsiString used to store ANSI Character, wideString used to store Unicode Character.
• 2.1.6 Array
Array is a single variable that can be used to store a set of similar data. to make differrent path array using element number in the right of array name : view the example: var day:array[1..7] of AnsiString; begin day[1]:='Sunday'; day[2]:='Monday'; . . . . . . edit1.text:=day[1];
• 2.1.7 Record

record data type used to store a set of data that may be different types, but interrelated. sample data using record Type ex: to save item data that contains; item code, item name and unit price. note the following program snippet :

type recitem=record code : String[6]; name : String [30]; Unitprice : Single; end; var itemm : recitem; begin itemm.code :='ns.001'; itemm.name :='naruto sipudden'; itemm.unitprice :=15000;
• 2.1.8 Enumeration and SubRange type
expressed sequence data with similar type. enumerate declarations exampes : type> color = (red, blue, green, yellow, orange, black, white ); var paintcolor : color; subrange declaration examples type mycolor = blue..orange; uppercase='A'..'Z'; value =0..100; var paintcolor=mycolor; testscores=value; finalvalue=uppercase;