Question: [Picture of error](https://i.stack.imgur.com/ZXQbM.png)

First program I make after hello world. Firstname, lastname and age. When using String on age, everything works as expected. I was told to use Int on age instead of String, but when I changed to Int and try to compile, I get this error: "cannot find symbol". I guess I have to do something completely different if I want age as an Int. What am I doing wrong? 

import java.util.Scanner;

public class Oppgave2 {

```
public static void main(String[] args) {

    Scanner scanner = new Scanner(System.in);

    System.out.println("Skriv inn fornavn: ");
    String fornavn = scanner.nextLine();

    System.out.println("Skriv inn etternavn: ");
    String etternavn = scanner.nextLine();

    System.out.println("Skriv inn alder: ");
    int alder = scanner.nextLine();

    System.out.println("Ditt navn er: " + fornavn + " " + etternavn);
    System.out.println("Din alder er: " + alder);
}

```

}

Answer: 
The type signatures of each give you a hint, but a rough summary is:
- Consumer `F -> ()`: Gets the effect object as an argument and calls something as an effect. Example: `Toast.makeText(context, effect.message(), duration).show();`

* Action `() -> ()`: Same as consumer but you don't need anything from the effect object. Example: `context.startActivity(new Intent(MyActivity.class))`
* Function `F -> E`: Blocking transformation from effect to a new event. Can be used if you know exactly one event will be emitted and you can safely do it as a blocking call. Example: `return Event.lookupResult(repository.get(effect.key()))`
* Transformer `Observable<F> -> Observable<E>`: The most powerful API, a full rx that can do anything to transform a stream of effects to a stream of events, including emitting more than one event per effect or even emitting events without receiving an effect first. Example: `effects.flatMap(effect -> return loadData(effect.uri())).map(Event::dataLoaded)` (edited)
Here is how each of these work,

```
╔═════════════╤═══════════════════════════╤═════════════════════╗
║     Type    │  Receives effect object?  │ Can produce events? ║
╠═════════════╪═══════════════════════════╪═════════════════════╣
║ Action      │            No             │         No          ║
║ Consumer    │            Yes            │         No          ║
║ Transformer │            Yes            │         Yes         ║
╚═════════════╧═══════════════════════════╧═════════════════════╝

```