Simple Function Example Kotlin Program

Definition

A function is a block of code written to perform a task. A function may be a parameterized function or a parameter-less function. A function may return a value or it may not return a value. The name of a function starts with a small letter and then follows CamelCase.

Syntax

fun method_name(){
//Functionality code
}

Function Example Program

fun main(args: Array < String > ) {
    val num1 = 11
    val num2 = 6

    //Calling function with no parameters and return type
    print()
    //Calling function with 2 parameters num1 and num2 and assigning the result to num3
    val num3 = add(num1, num2)

    //Printing result
    println("After addition of num1 and num2, the result is : " + num3)
}

//Function with parameters and Int return type
fun add(i: Int, j: Int): Int {
    return i + j
}

//Function without parameters and no return type
fun print() {
    println("I am inside print function.")
}

Sample Output

I am inside print function.
After addition of num1 and num2, the result is : 17

How It Works

Here is a step-by-step walkthrough of how the Kotlin program for Simple Function Example Kotlin Program runs, line by line:

1. fun main(args: Array < String > ) { — defines a function used by the program.
2. val num1 = 11 — declares or assigns a value the program uses.
3. val num2 = 6 — declares or assigns a value the program uses.
4. print() — writes a line of output shown in the sample output.
5. val num3 = add(num1, num2) — declares or assigns a value the program uses.
6. println("After addition of num1 and num2, the result is : " + num3) — writes a line of output shown in the sample output.
7. fun add(i: Int, j: Int): Int { — defines a function used by the program.
8. return i + j — returns the computed result.

After running it, compare your console output with the Sample Output above. Try changing the values and re-running the program to see how the result changes — experimenting is the fastest way to understand the logic.