Static functions

Static functions are functions that can be invoked without creating multiple instances of a class. Static functions avoid code duplication and can be reused.

Let's take a look at how to write a static function in Kotlin.

Consider the following code for 15a_StaticMethods.kts:

object MyUtil {
 fun foo(){
        println("Static function foo() is invoked")
    }
}

MyUtil.foo()

Note that we declared an object MyUtil and defined a function foo(). This is known as object declaration.

We invoked the function foo() directly using the object MyUtil. 

The output of the preceding code is as follows:

There are different ways to write static functions in Kotlin. We can define a companion object inside a class and define a static function in it. Consider the following code for 15b_StaticMethods.kts:

class Person {
    companion object {
        fun foo(){
            println("Static function foo() is invoked")
        }
    }
}
Person.foo()

The output is as follows:

We can also give a name to the companion object. Consider the following code for 15c_StaticMethods.kts:

class Person {
    companion object Util {
        fun foo(){
            println("Static function foo() is invoked")
        }
    }
}
Person.Util.foo()

The output is as follows:

In this section, we have covered the constructs that Kotlin provides. We will be using these constructs in the next few chapters.