Basically there is not much difference between them (method and functions).
//Car Class
class Car {
private String name;
private String color;
private int topSpeed;
public Car(String name, String color, int topSpeed) {
this.name = name;
this.color = color;
this.topSpeed = topSpeed;
}
public void accelerate() {
//vooom!
}
}
Differences
Method
- it is always called using the object of that class in which the method is written. In other words, it is a piece of code that is called by a name that is associated with an object.
- it is implicitly passed on the object on which it was called.
- It is able to operate on data that is contained within the class (remembering that an object is an instance of a class – the class is the definition, the object is an instance of that data).
// Example of a Method
//Java
Car car = new Car ("polo", "Green", 200);
car.accelerate();
//Kotlin
val car = Car ("polo", "Green", 200)
car.accelerate()
Function
- a function is a method which you can call without creating objects. In other words, a function is a piece of code that is called by name and is not associated with an object.
- It can be passed data to operate on (i.e. the parameters) and can optionally return data (the return value).
- All data that is passed to a function is explicitly passed.
Example of a Function
// Java Code
public class HelloWorld{
protected void main(ArrayList<String> args){
greet();
}
private void greet(){
System.out.print("Hello World!");
}
}
// Kotlin Code
class HelloWorld{
fun main(args: Array<String>){
greet()
}
fun greet(){
println("Hello World!")
}
}
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Further Reading
- Kotlin Method Examples
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