Code after lecture04

04/ArrayListClient.java

+import java.util.ArrayList;
+import java.util.TreeSet;
+
+public class ArrayListClient {
+    // Set<String> set = new TreeSet<>();
+    public static void main(String[] args) {
+        IList<String> list = new OurArrayList<>();
+        for (int i = 0; i < 19; i++) {
+            list.add("" + i + "!");
+        }
+        System.out.println(list);
+
+        /*
+        for (String s : list) {
+
+        }
+         */
+
+        /*
+        int[] =======>   [int][int][int].....
+        Object[] ====>   [ | ][ | ][ | ]
+                           v    v    v
+
+         */
+    }
+}
\ No newline at end of file

04/IList.java

+public interface IList<E> {
+    public int size();
+    public void set(int idx, E elem);
+    public E get(int idx);
+
+    public void clear();
+
+    public void add(int idx, E elem);
+    public void add(E elem);
+}

04/OurArrayList.java

+public class OurArrayList<E> implements IList<E> {
+    private E[] data;
+    private int size;
+
+    // size vs. capacity
+    // current size = 0
+    // max size (capacity) = 10
+
+    public OurArrayList() {
+        this.data = (E[])new Object[10];
+        this.size = 0;
+    }
+
+    //[1, 2, 3]
+    public String toString() {
+        String elements = "";
+        for (int i = 0; i < this.size; i++) {
+            elements += this.data[i] + ", ";
+        }
+        if (elements.length() > 0) {
+            elements = elements.substring(0, elements.length() - 2);
+        }
+        return "[" + elements + "]";
+    }
+
+
+
+    /**
+     * Puts element at index idx, shifting over everything after to the right.
+     * @param idx
+     * @param element
+     * For example, idx = 2, element = 42
+     * [1, 2, 3, 4, 5]
+     *        ^
+     * [1, 2, 42, 3, 4, 5]
+     */
+    public void add(int idx, int element) {
+
+    }
+
+    @Override
+    public int size() {
+        return this.size;
+    }
+
+    @Override
+    public void set(int idx, E elem) {
+        if (idx < 0 || idx > this.size) {
+           throw new IllegalArgumentException("blah");
+        }
+        else if (idx == size) {
+            add(elem);
+        }
+        this.data[idx] = elem;
+
+    }
+
+    public E get(int idx) {
+        return null;
+    }
+
+    @Override
+    public void clear() {
+        this.size = 0;
+    }
+
+    public void add(E elt) {
+        if (this.size == this.data.length) {
+            E[] newData = (E[])new Object[this.size * 2];
+            for (int i = 0; i < this.data.length; i++) {
+                newData[i] = this.data[i];
+            }
+            this.data = newData;
+        }
+        this.data[size] = elt;
+        this.size++;
+    }
+
+    @Override
+    public void add(int idx, E elem) {
+
+    }
+
+
+}