How to store a Scanner input and have it correspond with an array? Then pick a random element from that array

Working on a beginner java project.

The idea of the program is to take in user's favorite genre and return a random recommendation based on a top 10 (starting with 3 now) list of books in each genre.

My main question is how could I take in their input, make it correspond to the right array and print out a random element from that array in the getRecommendation() method.

Code below (left out imports and public class):

public WhatBook() {
	
	System.out.println("Hello, what genre of book are you in the mood for?");
		System.out.println("Please enter: \n1 for Horror\n2 for Adventure\n3 for Crime\n4 for War\n5 for Scifi");
		while (true) {
		Scanner scanGenre = new Scanner(System.in);
		int bookGenre = scanGenre.nextInt();
		
		if (bookGenre < 1 || bookGenre > 5) {
			System.out.println("Please choose from the genres from 1 to 5.");
		} else {
			System.out.println(bookGenre + "? Great choice! Let's get some recommendations for you.");
			break;
		}
		
	}


public static String getRecommendation() {

	// pick random element of the entered genre array
	// create random object
	int rnd = new Random().nextInt(array.length);
	return array(rnd);

}

// public arrays
String[] horror = { "The Shining", "The Stand", "The Haunting of Hill House" };
String[] adventure = { "Into Thin Air", "Hatchet", "The Call of the Wild" };
String[] crime = { "In Cold Blood", "Devil in the White City", "Helter Skelter" };
String[] war = { "The Things They Carried", "All Quiet on the Western Front", "Catch-22" };
String[] scifi = { "Dune", "1984", "Ender's Game" };

public static void main(String[] args) {

	WhatBook user1 = new WhatBook();

}

I tried using a switch loop in the constructor to set each int value to its corresponding array. Like:

switch (bookGenre) {

case 1:
bookGenre = horror[0];
break;
etc...

but this doesn't work.

Any ideas how to store the bookGenre int value to match its array?

you're looking for the concept of a field.

I would make an Array or Arrays (a 2D array), from your existing book arrays:

String[][] genres = { horror, adventure, crime, war, scifi };

Just make sure that they are listed in the same order as your menu system. Since your menu starts at 1, we'll have to subtract 1 from the user choice to make zero based like the array.

Next, I would change your getRecommendation() method to receive an array. Additionally, I would declare a static instance of Random that can be re-used over and over, instead of creating a new one each time:

private static Random R = new Random();
public static String getRecommendation(String[] array) {
// pick random element of the entered genre array
// create random object
int rnd = R.nextInt(array.length);
return array[rnd];
}

Lastly, just make sure that the number the user entered is within the bounds of your array, and pass the corresponding array to the method:

int bookGenre = scanGenre.nextInt();
if (bookGenre >=1 && bookGenre <= genres.length) { // between 1 and genres.length to match the displayed menu
System.out.println(bookGenre + "? Great choice! Let's get some recommendations.");
String book = getRecommendation(genres[bookGenre - 1]); // subtract 1 to make it zero based
System.out.println("Your recommendation: " + book);
}
else
{
System.out.println("Invalid Choice.");
}

Here's the whole thing put together:

import java.util.Random;
import java.util.Scanner;
public class WhatBook {
private static Random R = new Random();
// public arrays
String[] horror = { "The Shining", "The Stand", "The Haunting of Hill House" };
String[] adventure = { "Into Thin Air", "Hatchet", "The Call of the Wild" };
String[] crime = { "In Cold Blood", "Devil in the White City", "Helter Skelter" };
String[] war = { "The Things They Carried", "All Quiet on the Western Front", "Catch-22" };
String[] scifi = { "Dune", "1984", "Ender's Game" };
String[][] genres = { horror, adventure, crime, war, scifi };
public WhatBook() {
System.out.println("Hello, what genre of book are you in the mood for?");
System.out.println("Please enter: \n1 for Horror\n2 for Adventure\n3 for Crime\n4 for War\n5 for Scifi\n");
Scanner scanGenre = new Scanner(System.in);
System.out.print("Your choice: ");
int bookGenre = scanGenre.nextInt();
if (bookGenre >=1 && bookGenre <= genres.length) {
System.out.println(bookGenre + "? Great choice! Let's get some recommendations.");
String book = getRecommendation(genres[bookGenre - 1]);
System.out.println("Your recommendation: " + book);
}
else
{
System.out.println("Invalid Choice.");
}
}
public static String getRecommendation(String[] array) {
// pick random element of the entered genre array
// create random object
int rnd = R.nextInt(array.length);
return array[rnd];
}
}