CODEWITHSUNDEEP
javaarraylist
Chris
Chris

Reputation: 193

Arraylist of classes

In my hw assignment my professor says to create a data field of type ArrayList. He wants them to be instances of a class. I'm not exactly sure what that means, but my guess is 

    ArrayList<CLassName> list = ArrayList<ClassName>();

Can anyone confirm this for me?

Upvotes: 1

Views: 60

Answers (3)

sendon1982
sendon1982

Reputation: 11234

You can use something like this:

List<String> list = new ArrayList<String>();

Since Java SE 1.7, it can a little simpler:

List<String> list = new ArrayList<>();

Upvotes: 3

tbodt
tbodt

Reputation: 16987

Yes, that's right. I do, however, recommend this instead:

List<ClassName> list = new ArrayList<ClassName>();

That way you can change the type of list in just one place instead of two.

Upvotes: 0

Anubian Noob
Anubian Noob

Reputation: 13596

Yes.

NOTE: The rest is background knowledge about ArrayLists.

Let's say you want an ArrayList of Strings. Keep in mind Strings are Objects.

// Creates ArrayList
ArrayList<String> list = ArrayList<String>();

// Adds elements to ArrayList
list.add("Hello");
list.add("world!");

// Iterate through ArrayList
for (String str : list) {
    // Print the String in the list.
    System.out.print(str + " ");
}
// Print newline character.
System.out.print("\n");

The for (String str : list) is a for each loop which allows you to iterate through each element in the list.

Upvotes: 0

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