Adding items

Add items with addItem.

Adding items (add)

In this lesson we'll meet the add method. cart.add(...) puts a new item at the end of the list:

ArrayList<String> cart = new ArrayList<>();
cart.add("Apple");
cart.add("Bread");
System.out.println(cart);  // [Apple, Bread]

Each add call adds one more item. Since ArrayList is dynamic, the item count does not need to be known in advance. The final cart holds all added items.

Cart size

cart.size() gives the number of items in the cart. For an empty cart it returns 0:

ArrayList<String> cart = new ArrayList<>();
System.out.println(cart.size());  // 0
cart.add("Apple");
System.out.println(cart.size());  // 1

Arrays have a length field (no parens); ArrayList has a size() method (parens). This is a common source of mistakes; be careful.

Exercise Add two items and print

Add two items to the cart from the previous lesson. Add cart.add("Apple") and cart.add("Bread"). Print the cart and its size with System.out.println(cart) and System.out.println(cart.size()).

Show example solution

import java.util.ArrayList;

public class Main {
    public static void main(String[] args) {
        ArrayList<String> cart = new ArrayList<>();
        cart.add("Apple");
        cart.add("Bread");
        System.out.println(cart);
        System.out.println(cart.size());
    }
}

Test yourself

Complete the add call
```
cart.____("Apple");
```
Show answer
```
cart.add("Apple");
```
What does cart.add("Apple") do?
- Removes Apple from the cart
- Adds Apple to the cart
- Empties the cart
- Shows Apple
Show answer

Adds Apple to the cart — add adds an item to the list.
Match the list methods

add

Add an item
size()

Item count
cart

Cart variable
println

Print

Next lesson: Calculating totals

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