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Janak  bista
Janak bista

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Extension Function

Kotlin gives the programmer the ability to add more functionality to the existing classes, without inheriting them.

This is achieved through a feature known as extensions.

When a function is added to an existing class it is known as Extension Function.

To add an extension function to a class, define a new function appended to the class name.

For Example :

fun main() {
 val list = mutableListOf(1,2,3,4)
fun MutableList<Int>.swap(index1: Int, index2: Int) {
    val tmp = this[index1] // 'this' corresponds to the list
    this[index1] = this[index2]
    this[index2] = tmp

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Output : [3,2,1,4]

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