Function is a set of code that performs a specific task. In Kotlin, we can define our own functions to be called later whenever we need to perform that task. In this post, we'll learn how to define functions, call them, and return values from them.
In Kotlin, we define functions using the fun keyword. For example, let's say we want to define a function that prints a greeting message. We can do so like this:
fun printGreeting() {
println("Hello, world!")
}
We can also define functions that take in arguments. For example, let's say we want to define a function that prints a greeting message with a name. We can do so like this:
fun printGreeting(name: String) {
println("Hello, $name!")
}
We can also define functions that return values. For example, let's say we want to define a function that calculates the sum of two numbers. We can do so like this:
fun sum(a: Int, b: Int): Int {
return a + b
}
We call functions by simply using their names followed by parentheses (). For example, we can call the printGreeting() function we defined earlier like this:
printGreeting() // prints "Hello, world!"
If we defined a function that takes in arguments, we need to pass in the arguments within the parentheses (). For example, we can call the printGreeting(name: String) function we defined earlier like this:
printGreeting("John") // prints "Hello, John!"
If we defined a function that returns a value, we need to store the return value in a variable. For example, we can call the sum(a: Int, b: Int): Int function we defined earlier like this:
val result = sum(1, 2) // result is 3
As we saw in the previous section, we can define functions that return values. In Kotlin, we use the return keyword to return a value from a function. For example, let's say we want to define a function that calculates the sum of two numbers and returns the result. We can do so like this:
fun sum(a: Int, b: Int): Int {
return a + b
}
We can also return values without explicitly using the return keyword. For example, let's say we want to define a function that calculates the sum of two numbers and returns the result. We can do so like this:
fun sum(a: Int, b: Int): Int = a + b
In the latter example, we return the value of a + b by simply assigning it to the function name sum.
That's it for this post! In summary, we learned how to define functions, call them, and return values from them.