数组随机问题

Question

we create a small quiz app for the university in a project. But we are not programmers. I have now created 17 questions and packed them into 17 arrays. The question is always at position 0 of the array. The answer is always at position 1 of the array. Everything also works correctly. But I would like to insert a random order. I already tried Switch Case or randomshuffle, no success and the answers no longer match the questions.

I would be very happy if someone could help us. Thank you very much.

This is the 17th array. I think it makes no sense to show them all.

    String[] frage17 = new String[5];
    frage17[0] = "Marke";
    frage17[4] = "Produkt/Dienstleistung";
    frage17[2] = "Preis/Verkaufsbedingungen";
    frage17[3] = "Distribution";
    frage17[1] = "Kommunikation";

Right now this is my manual order. How can I now create a random order without having to change my arrays?

    fragen.add(0, frage17);
    fragen.add(1, frage11);
    fragen.add(2, frage13);
    fragen.add(3, frage4);
    fragen.add(4, frage7);
    fragen.add(5, frage1);
    fragen.add(6, frage5);
    fragen.add(7, frage16);
    fragen.add(8, frage9);
    fragen.add(9, frage8);
    fragen.add(10, frage10);
    fragen.add(11, frage2);
    fragen.add(12, frage12);
    fragen.add(13, frage14);
    fragen.add(14, frage15);
    fragen.add(15, frage6);
    fragen.add(16, frage3);

Output at the end:

ArrayList<String[]> getFragen() {
    return fragen;

Answer 1

Ideally, what you need is a Map between the question and answer, so that even if the questions are shuffled, you always get the right answer.

Map<String,String> map = new HashMap<>();
map.put("How are you?","I am fine"); // similarly for all questions

Then use map.entrySet() to get EntrySet<Key,Value> pair. Additionally, you can even use Collections.shuffle(new ArrayList<>(map.entrySet())); to shuffle the obtained EntrySet . Best wishes!

Answer 2

Judging by what you want to accomplish, it would make more sense to create a class as per the requirements for each frage item and then create an array of such items.

From the code you posted, it seems like you are using Java, thus, this is the part of the code to create a class:

public static class frage   {
    private String data01;
    private String data02;
    private String data03;
    private String data04;
    private String data05;


    public frage(String data01, String data02, String data03, String data04, String data05) {
        this.data01 = data01;
        this.data02 = data02;
        this.data03 = data03;
        this.data04 = data04;
        this.data05 = data05;
    }

    public String getData01()   {
        return data01;
    }

    public String getData02()   {
        return data02;
    }

    public String getData03()   {
        return data03;
    }

    public String getData04()   {
        return data04;
    }

    public String getData05()   {
        return data05;
    }
}

This class is equivalent to the array of 5 strings that you created. To create an item of this class, do it like so:

frage frage1 = new frage("Marke", "Produkt/Dienstleistung", "Preis/Verkaufsbedingungen", "Distribution", "Kommunikation");

And similarly, create the rest of your objects. Modify the name of data01 and other variables (strings) that are declared inside the class as per your convenience.

Since you mentioned that you do not have coding experience, to get the data from an item you can use:

String result = frage1.getData01();

Here, frage1 was the item that I created in the previous code snippet. And the data present inside data01 of frage1 is now present inside result , you can use this data however you like.

Now, create a list of items of frage , in the code snippet above, I create frage1 , in the same manner, create other 16 items (or as many as you want)!

Create an ArrayList like so:

ArrayList<frage> fragen = new ArrayList<frage>();

And put these items inside the array list created above:

fragen.add(frage1);

Similarly, add the rest of the items that you create. Now, whenever you want to get a random frage item from the arraylist, start by importing java.util.Random and creating an object of Random , ie add this to the very beginning of your program:

import java.util.Random;

Random rand = new Random();

Now, whenever in the program you want to get a random item of frage , use this code:

frage random_item = fragen.get(rand.nextInt(fragen.size()));

And so, you will get a random frage item that will contain all the details about your question. Here, frage was the name of the class that we created, fragen was the name of the ArrayList that we created and rand was the instance of Random that should be created at the beginning.

If you want to get data01 from the random_item that you just got, use:

String data = random_item.getData01();

And data will now contain the value of data01 . Hope this was of some help. If you want to clarify something, post it in the comments and I shall try my best to help ;)

Answer 3

You should create a class that holds each question and answer instead of using an array here. The rule of thumb is that arrays should be used for a sequence of similar objects. In this case, "question" and "answer" are not similar, so you shouldn't use an array.

When you use this approach, shuffling the questions becomes pretty simple. You create an List with instances of your new class then shuffle that list.