Types of Variables - Kotlin Tutorials for beginners

This beginners tutorial is on types of variables in Kotlin, values each of these types take and memory allocated for each type.

Types of variables in Kotlin are

Integer

Floating point

Boolean

Characters and Strings

They differ in the

Type of value they take

Memory allocated when an object of a type is created
And operations that can be performed

when you declare a variable, an object is created and memory is allocated to it, the size of memory allocated depends on the type of the variable. Check Variables in kotlin for more on Variables.

1.Integer

Integer again has four types

Type	Byte	Short	Int	Long
Memory allocation	8 bits	16 bits	32 bits	64 bits
Range	-128 to 127	-32768 to 32767	-2,147,483,648 to 2,147,483,647	very large values
Example	var x : Byte = 97	var x : Short = 10000	var x = 6	var x = 6L
Operations performed	conversion to other types, mathematical operation	conversion to other types, mathematical operation	conversion to other types, mathematical operation	conversion to other types, mathematical operation

var x = 97, can also mean variable of type Int, if you want it to be of type Byte, you will have to explicitly mention the keyword “Byte” .

var x = 10000, can also mean variable of type Int, if you want it to be of type Short, you will have to explicitly mention the keyword “Short”.

If integer assigned is too large, the compiler will consider it as Long internally

var x = 6, can also mean variable of type Int, if you want it to be of type Long, you will have to explicitly mention it by adding “L” at the end.
conversion to other types can be done with the help functions toByte(), toShort(), toInt(), toLong(), toFloat(), toDouble(), toChar()
mathematical operations such + , – , * , / , % can be performed

2. Floating points

Float has two types

Type	Float	Double
Memory allocation	32 bits	64 bits
Range	-2,147,483,648 to 2,147,483,647	very large values
Example	var x = 123.5	var x = 123.5F
Operations performed	conversion to other types, mathematical operation	conversion to other types, mathematical operation

when a variable is declare using a fraction number, the compiler thinks of it as Double by default.
to explicitly mention the type as Float, add “F” or “f” at the end, if this number contains 6 or 7 decimal digit, it would be rounded.
If the double value contians more than 6-7 digits, the value will be rounded
conversion to other types can be done with the help functions toByte(), toShort(), toInt(), toLong(), toFloat(), toDouble(), toChar()
mathematical operations such + , – , * , / , % can be performed

3. Boolean

The boolean type takes two values “true” or “false”

Type	Boolean
Memory allocation	1 bit
Range	true or false
Example	var isBoolean = true, var isBoolean = false
Operations performed	logical operations

logical operations such as AND ( && ), OR ( || ) and nagation (!)

4. Characters and Strings

Type	Characters
Memory allocation	8 bits
Range	-128 to 127
Example	var alphabet = ‘A’

String is used to hold multiple characters

Example for string var greeting = “Hello”
Strins are immutable – meaning the value assigned doesnot change
Operations on string involve converting the string to uppercase/lowercase, concatination etc

Additional Info

Other number formats supported in Kotlin

Type	Binary Numbers	Hexadecimal Numbers	Octal Numbers
Declaration	with prefix 0b	with prefixing 0x	Not supported
Example	var x = 0b10	var y = 0xAB	_