Basic Example :-
fun addNumbers(n1: Double, n2: Double): Int { //Int is Returntype
val sum = n1 + n2
val sumInteger = sum.toInt()
return sumInteger
}
fun addNumbers(n1: Double, n2: Double): Unit { //Returning Nothing & can be blank also
val sum = n1 + n2 (No need to define)
val sumInteger = sum.toInt()
return sumInteger
}
Function as Expression :-
fun max(a:Int, b:Int):Int {
if (a >b ) {
return a
}
else {
return b
}
}
can be changed into -
fun max(a:Int, b:Int):Int = if (a>b) a else b
Default Function :- Interpolation
- Takes Default value when no arguments is passed.
main()
var result = findVolume(2,3) //here takes default h as 10
print(result)
var result = findVolume(2,3,8) //values already provided , so no default taken
print(result)
fun findVolume(l:Int,b:Int,h:Int=10) { //takes default h as 10 if not provided
return l*b*h }
Named Parameter :-
No matter with sequence of arguments in function.
Name of Arguments will be same in calling and called function.
main()
findVolume(h=30,b-=5,l=7)
findVolume(b=22,l=9)
fun findVolume(l:Int,b=int,h:Int=10) { //No matter of sequence, Default parameter also provided
print(lenght $l)
print(breadth $b)
print(height $h)
}
Extension Function :-
Add new function to any class in main.
New function will be static.
eg-1
main() {
var student = Student()
println("passed status :" +student.ispassed(57))
println("passed status :" +student.isScholar(57)) }
fun Student.isScholar(mark :Int):Boolean { //This is extension function
return mark > 95 }
class Student {
fun ispassed(mark : Int) : Boolean {
return mark > 40 }
main() {
var str1 = "man"
var str2 = "eats"
var str3 = "apple"
println(str3.add(str1,str2)
fun String.add(s1:String,s2.String):String { //extension function
return this + s1 + s2 }
*Extenstion function work String, Int etc as datatype is class in Kotlin
Infix Function :-
Same as Extension Function but work with Single Parameter.
prefix of Infix
main() {
val x:Int = 6
val y:Int = 10
val greaterVal = x greater y //x.greater(y) new way of defining fun
println(greaterVal)
infix funtion Int.greater(other.Int) : Int {
if (this>other)
return this
else
return other } }
Tailrec Fuction :-
use Recursion.(calling function within own function)
Avoid Stackoverflow exception
tailrec fun findFixPoint(x: Double = 1.0): Double
= if (Math.abs(x - Math.cos(x)) < eps) x else findFixPoint(Math.cos(x))
