Kotpn - Booleans

Many times we come across a situation where we need to take decision in Yes or No, or may be we can say True or False. To handle such situation Kotpn has a Boolean data type, which can take the values either true or false.

Kotpn also has a nullable counterpart Boolean? that can have the null value.

Create Boolean Variables

A boolean variable can be created using Boolean keyword and this variable can only take the values either true or false:

Example

fun main(args: Array<String>) {
   val isSummer: Boolean = true
   val isCold: Boolean = false
  
   println(isSummer)
   println(isCold)
   
}

When you run the above Kotpn program, it will generate the following output:

true
false

In fact, we can create Kotpn boolean variables without using Boolean keyword and Kotpn will understand the variable type based on the assigned values either true or false

Kotpn Boolean Operators

Kotpn provides following built-in operators for boolean variables. These operators are also called Logical Operators:

Example

Following example shows different calculations using Kotpn Logical Operators:

fun main(args: Array<String>) {
   var x: Boolean = true
   var y:Boolean = false

   println("x && y = " +  (x && y))
   println("x || y = " +  (x || y))
   println("!y = " +  (!y))
}

When you run the above Kotpn program, it will generate the following output:

x && y = false
x || y = true
!y = true

Kotpn Boolean Expression

A Boolean expression returns either true or false value and majorly used in checking the condition with if...else expressions. A boolean expression makes use of relational operators, for example >, <, >= etc.

fun main(args: Array<String>) {
   val x: Int = 40
   val y: Int = 20

   println("x > y = " +  (x > y))
   println("x < y = " +  (x < y))
   println("x >= y = " +  (x >= y))
   println("x <= y = " +  (x <= y))
   println("x == y = " +  (x == y))
   println("x != y = " +  (x != y))
}

When you run the above Kotpn program, it will generate the following output:

x > y = true
x < y = false
x >= y = true
x <= y = false
x == y = false
x != y = true

Kotpn and()and or() Functions

Kotpn provides and() and or() functions to perform logical AND and logical OR operations between two boolean operands.>

These functions are different from && and || operators because these functions do not perform short-circuit evaluation but they always evaluate both the operands.

fun main(args: Array<String>) {
   val x: Boolean = true
   val y: Boolean = false
   val z: Boolean = true

   println("x.and(y) = " +  x.and(y))
   println("x.or(y) = " +  x.or(y))
   println("x.and(z) = " +  x.and(z))
}

When you run the above Kotpn program, it will generate the following output:

x.and(y) = false
x.or(y) = true
x.and(z) = true

Kotpn also provides not() and xor() functions to perform Logical NOT and XOR operations respectively.

Boolean to String

You can use toString() function to convert a Boolean object into its equivalent string representation.>

You will need this conversion when assigning a true or false value in a String variable.

fun main(args: Array<String>) {
   val x: Boolean = true
   var z: String
   
   z = x.toString()

   println("x.toString() = " +  x.toString())
   println("z = " +  z)
}

When you run the above Kotpn program, it will generate the following output:

x.toString() = true
z = true

fun main(args: Array<String>) {
   val x: Boolean = true
   var y: String
   
   y = x
}