Printing ArrayList into output?

Question

So, i have ArrayList which i store animals in.

private ArrayList<Animal> catalog = new ArrayList<>();

Now, i need to print the catalog into my output when i press 4 into my output.

case 4:
                System.out.println("List of animals: ");
                printIt();   //Function to print catalog
                break;

I tried to do it with

    private boolean InList(String name) {
    for (int i = 0; i < catalog.size(); i++) {
        if (name.equalsIgnoreCase(catalog.get(i).getName())) {
            return true;
        }
    }
    return false;
}

But it's not working. Can you guys help me to get this piece of code?

When i try to print only "catalog" which are animals stored in, i will get "[animalcatalogjava.Animal@33909752]" printIt is here private String printIt(){ String animal = name; //catalog.add(); return animal; } — Jan Kučaba, Apr 27 '16 at 19:27

score 0 · Answer 1 · answered Apr 27 '16 at 19:34

0

Do something like this if you want it to return a String.

String printIt(ArrayList<Animal> animals) {
String temp = "";
for(Animal animal : animals) {
temp += animal.getName() + "\n";
}
return temp;
}

Although I don't see a need for that, just print it right away.

void printIt(ArrayList<Animal> animals) {
for(Animal animal : animals) {
System.out.println(animal.getName());
}
}

answered Apr 27 '16 at 19:34

Austin

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Thank you. Used 2nd option. You're right, better one :p – Jan Kučaba Apr 27 '16 at 20:39

score 0 · Answer 2 · answered Apr 27 '16 at 19:34

0

Defining a method that prints is maybe too much, you can just do

System.out.println("List of animals: "+ catalog );

but for that you must override the toString method in the class animal...

if you dont override that you will get something printed like

[animalcatalogjava.Animal@33909752]

that is the defaukt to string of the object...

something like in the format:

package.class@hashcode..

answered Apr 27 '16 at 19:34

ΦXocę 웃 Пepeúpa ツ

47,427
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Thanks. Not entirely sure "how to override" toString, but it works now. – Jan Kučaba Apr 27 '16 at 20:36

score 0 · Answer 3 · answered Apr 27 '16 at 19:40

you need to override toString() method for printing user friendly names of the objects and it helps in debugging.

equals() method for comparing two animal objects are same or not.

For more information on how or when to override Object class methods https://docs.oracle.com/javase/tutorial/java/IandI/objectclass.html

Printing ArrayList into output?

3 Answers3