CODEWITHSUNDEEP
javaarraysobjectmethodsjava.util.scanner
Phil_oneil
Phil_oneil

Reputation: 267

Multiple object in array (java)

I want to create objects using the result from Scanner and add them to an array.

However, each time I ask for user input for the second time, it just overwrites the first object.

How can I add multiple objects to the array?

Here's my code:

public void ajoutadd() {
    int i=0;
    boolean boucle=true;
    while(i!=2){
        Scanner thegame = new Scanner(System.in);
        System.out.print("name: \n");
        String jname = lejeu.nextLine();
        System.out.print(jname);
        Scanner qty = new Scanner(System.in);
        System.out.print("qty \n");
        int jqty = qty.nextInt();
        Scanner cat = new Scanner(System.in);
        System.out.print("cat: \n");
        String categ = cat.nextLine();
        Scanner price = new Scanner(System.in);
        System.out.print("price: \n");
        int jprice = price.nextInt();
        Game agame = new Game(jname,jqty,categ,jprice);
        System.out.print(unjeu.Nom);

        // creating the array to contain the game(s)
        ArrayList<Game> thegame = new ArrayList<Game>(); 

        thegame.add(new Game(jname,jqty,categ,jprice));

        // actually only display 1 object that is overwritten
        // each time after the loop
        System.out.println(thegame);

        i=i++;
    }
}

Upvotes: 3

Views: 4065

Answers (3)

Panther
Panther

Reputation: 3339

Move initialization of list outside the loop. Currently, you are creating list object everytime in loop. Hence losing the reference to existing one.

public  ArrayList<Game> ajoutadd() {
    int i=0;
    boolean boucle=true;
     ArrayList<Game> thegame = new ArrayList<Game>(); 
    while(i!=2){
    Scanner thegame = new Scanner(System.in);
    System.out.print("name: \n");
    String jname = lejeu.nextLine();
    System.out.print(jname);
    Scanner qty = new Scanner(System.in);
    System.out.print("qty \n");
    int jqty = qty.nextInt();
    Scanner cat = new Scanner(System.in);
    System.out.print("cat: \n");
    String categ = cat.nextLine();
    Scanner price = new Scanner(System.in);
    System.out.print("price: \n");
    int jprice = price.nextInt();
    Game agame = new Game(jname,jqty,categ,jprice);
    System.out.print(unjeu.Nom);
   //creating the array to contain the game(s)
    thegame.add(new Game(jname,jqty,categ,jprice));
   each time after the loop


    i++;

    }
  System.out.println(thegame); 
  return  thegame;


}

Upvotes: 1

Simba
Simba

Reputation: 1651

Your loop is not actually overwriting the first value. It is just creating a new ArrayList every time you loop through.

You should create one ArrayList and continously add to it.

ex.

ArrayList<Game> games = new ArrayList<Game>();
while(...) {
   ...
   games.add(...);
   ...
}

Couple notes:

  • You do not have to create a new Scanner for every scan you can just use the same one (Also initialize it outside the loop like the array list).

  • i=i++ could just be i++, i++ increments the variable i, it is different than i + 1. It is equivalent to i = i + 1.

  • It is good practice to use the List interface for the ArrayList variable so that your code will work the same regardless of which List implementation you use.

Upvotes: 2

Elliott Frisch
Elliott Frisch

Reputation: 201467

Create one Scanner outside the loop and one List instance (and I suggest you use the interface). Like,

public void ajoutadd() {
    int i = 0;
    boolean boucle = true;
    Scanner thegame = new Scanner(System.in);
    List<Game> thegame = new ArrayList<>();
    while (i != 2) {
        System.out.print("name: \n");
        String jname = thegame.nextLine();
        System.out.print(jname);
        System.out.print("qty \n");
        int jqty = thegame.nextInt();
        System.out.print("cat: \n");
        String categ = thegame.nextLine();
        System.out.print("price: \n");
        int jprice = thegame.nextInt();
        Game agame = new Game(jname, jqty, categ, jprice);
        System.out.print(unjeu.Nom);
        thegame.add(new Game(jname, jqty, categ, jprice));
        System.out.println(thegame);
        i++; // <-- not i = i++;
    }
}

Upvotes: 1

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