Data Types

The data types of an entity specify its associated meaning, constraints, possible values, operations, functions, and storage mode.

A variable is nothing but a name given to a storage area that our programs can manipulate. Each variable in TRObject has a specific type, which determines the size and layout of the variable's memory; the range of values that can be stored within that memory; and the set of operations that can be applied to the variable.

A type declaration is used to declare the data type of an identifier. The syntax of a type declaration is as follows:

var
  days : integer;

Integer Types

Type	Description
Byte	Values range from 0 to 255.
ShortInt	Values range from -128 to 127.
SmallInt	Values range from -32,768 to 32,767.
Integer	Values range from -2,147,483,648 to 2,147,483,647.
LongInt	Has the same range as Integer.
Int64	Values range from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807.
Cardinal	Values range from 0 to 4,294,967,295.
LongWord	Values range from 0 to 4,294,967,295.
UInt64	Values range from 0 to 18,446,744,073,709,551,615.

Example
TRObject Syntax

var
  age: Byte;
  temperature: ShortInt;
  year: SmallInt;
  population: Integer;
  distance: Int64;
  fileSize: Cardinal;
  largeNumber: UInt64;
  balance: LongInt;
  memorySize: LongWord;
{
  age = 25;
  temperature = -15;
  year = 1990;
  population = 1500000;
  distance = 10000000000;
  fileSize = 4000000;
  largeNumber = 1200000000000000000;
  balance = -5000000;
  memorySize = 3000000000;
  
  ShowMessage(age);
  ShowMessage(temperature);
  ShowMessage(year);
  ShowMessage(population);
  ShowMessage(distance);
  ShowMessage(fileSize);
  ShowMessage(largeNumber);
  ShowMessage(balance);
  ShowMessage(memorySize);
}

Base Syntax

var
  age: Byte;
  temperature: ShortInt;
  year: SmallInt;
  population: Integer;
  distance: Int64;
  fileSize: Cardinal;
  largeNumber: UInt64;
  balance: LongInt;
  memorySize: LongWord;
begin
  age := 25;
  temperature := -15;
  year := 1990;
  population := 1500000;
  distance := 10000000000;
  fileSize := 4000000;
  largeNumber := 1200000000000000000;
  balance := -5000000;
  memorySize := 3000000000;
  
  ShowMessage(age);
  ShowMessage(temperature);
  ShowMessage(year);
  ShowMessage(population);
  ShowMessage(distance);
  ShowMessage(fileSize);
  ShowMessage(largeNumber);
  ShowMessage(balance);
  ShowMessage(memorySize);
end;

Sr.No	Type & Description
1	Character Typically a single octet (one byte). This is an integer type.
2	Integer The most natural size of integer for the machine.
3	Real A single-precision floating point value.
4	Boolean Specifies true or false logical values. This is also an integer type.
5	Enumerated Specifies a user-defined list.
6	Subrange Represents variables, whose values lie within a range.
7	String Stores an array of characters.