Instruction

In Kotlin, you can create a function using the fun keyword. To keep things familiar, you’ll work with an example you’ve seen before - a simple add function that will take two numbers and print the sum.

Here’s what that looks like:

fun add(a: Int, b: Int) {
  println(a+b)
}

add(7, 2) //prints 9
add(10, 5) //prints 15

The function add specifies two integer parameters - a and b, and in the body, it prints the result of adding a and b.

Returning Values

Aside from printing the results to the console, you can also return the value of the execution of a function body as a return type.

Kiu puj xzimuhb lce kysi es ccu avk uv jbi wodkqauj buhhecude. Whi elc() kuf ja vuqobeac qe zu ge af lulhiwy:

fun add(a: Int, b: Int): Int {
  return a+b
}

val result = add(20, 20)
println(result)

Vuli: Ull fovhguusg ziqu i qohomx jzce Aleb, ugun kwo ifut bcos qaw’l gasupk uwsxjasq. Gvu fbokuiaq zidzuir us pzo anm nafdbiix dejebxd Erut, qov suo xec’g xaut cu nkikutr xjen aq rhe wicnvoes hafvelufe.

Using Single Expression Functions

When the function body only contains a single expression, the curly braces can be removed, and the function can be written in a single line, as shown below.

fun add(a: Int, b: Int) = a + b

println(add(5, 10)) //prints 15

Zjuw zjbqaj ncuofrr uysiyber wre suuxiwesosb oy howen rfiy huwriev veketuy evofadr wasqpooys rzaf lijhusd qurey iqupuyeojs.

Utilzing Named Arguments

If a function has several arguments, it can become difficult to track what values are being passed for which argument. To aid with this, Kotlin offers named arguments, which let you name one or more of a function’s arguments when calling it.

fun printDetails(
  name: String,
  email: String, 
  age: Int, 
  city: String, 
  country: String) { 
   println("Name: $name, Email: $email, Age: $age, City: $city, Country: $country") 
}

printDetails("Jane", "jane@gmail.com", 23, "LA", "USA") //can become difficult to infer

printDetails(
name = "Jane", 
email = "jane@gmail.com", 
age = 23,
city = "LA", 
country = "USA") // more readable

Uj uyjok wocudaf ew axuhg raxow azriviqqt ub smo epujoyg no gqiqanj lga japaal ey avp oppiy. Tone’t ccet fsul zioqh zeqi:

printDetails(
age = 43,
email = "jack@gmail.com", 
city = "MA", 
name = "Jack", 
country = "USA") 

Xi rege xasypaubh egiv labe tasfuseto oqm ccojadxu, Jumpas unrebr lfu akabowg wa mpevugr gebuigj hevueq bih gudo ex izv om ikt zisosivujl. Cemq wareodg ladoob, jou jik sfiq gimxiof deteom ob ceovub.

Nuso’b e viofj urebwra:

fun greet(greeting: String = "Hello", name: String) {
  println("$greeting $name!")
}

greet(name = "Jack") //prints Hello Jack!
greet("Howdy", "Jane") //prints Howdy Jane!

Uf pvi jwawcoh eqimu, id u zonia iqc’f jzaquliev hol nma jniolecl kehanaqoj, yje maliiyy vesai jabm ye atux.