lecture code repo

Author: joshHug

lec7_lists4/AList.java

@@ -1,43 +1,50 @@
 package lec7_lists4;
 
-public class AList {
+public class AList<Glorp> {
+    private Glorp[] items;
     private int size;
-    private int[] items;
 
     public AList() {
         size = 0;
-        items = new int[100];
+        items = (Glorp[]) new Object[100];
+    }
+    // 0, 0, 0, 0, 0, 0, 0, ...
+    // 3, 0, 0, 0, 0, 0, 0,
+    // 3, 7, 0, 0, 0, 0, 0,
+    //       ^ size = 2
+    //
+    // Observation: Next new item will go in position size
+    //              The last item is in position size - 1
+    //              Size is the number of items.
+
+    // resize the underlying array to the desired capacity
+    private void resize(int capacity) {
+        Glorp[] a = (Glorp[]) new Object[capacity];
+        System.arraycopy(items, 0, a, 0, size);
+        items = a;
     }
 
-    // [3, 4, 2, 0, 0, 0, ....]
-    //           ^ (size = 3)
-    // size is the location of the next add
-    // size - 1 location of the last item
-
-    public void addLast(int x) {
+    public void addLast(Glorp x) {
         if (size == items.length) {
             resize(size + 1);
         }
         items[size] = x;
         size += 1;
     }
 
-    private void resize(int newSize) {
-        int[] a = new int[newSize + 1];
-        System.arraycopy(items, 0, a, 0, size);
-        items = a;
-    }
-
-    public int getLast() {
+    public Glorp getLast() {
         return items[size - 1];
     }
 
-    public int get(int i) {
+    public Glorp get(int i) {
+        if (i >= size) {
+            throw new IllegalArgumentException("We don't have that much stuff");
+        }
         return items[i];
     }
 
-    public int removeLast() {
-        int itemToReturn = getLast();
+    public Glorp removeLast() {
+        Glorp itemToReturn = getLast();
         size -= 1;
         return itemToReturn;
     }

lec7_lists4/AListTest.java

@@ -11,7 +11,7 @@
 public class AListTest {
     @Test
     public void testAddAndGet() {
-        AList list = new AList();
+        AList<Integer> list = new AList<>();
         list.addLast(5);
         list.addLast(10);
 
@@ -22,7 +22,7 @@ public void testAddAndGet() {
 
     @Test
     public void testGetLast() {
-        AList list = new AList();
+        AList<Integer> list = new AList<>();
         list.addLast(7);
         list.addLast(14);
         list.addLast(21);
@@ -33,7 +33,7 @@ public void testGetLast() {
 
     @Test
     public void testRemoveLast() {
-        AList list = new AList();
+        AList<Integer> list = new AList<>();
         list.addLast(3);
         list.addLast(6);
         list.addLast(9);
@@ -50,15 +50,15 @@ public void testRemoveLast() {
         assertThat(list.removeLast()).isEqualTo(3);
     }
 
-    /*@Test
+    @Test
     public void add200Items() {
-        lec7_lists4.resizeExercise.AList list = new lec7_lists4.resizeExercise.AList();
+        AList<Integer> list = new AList<>();
         for (int i = 0; i < 200; i += 1) {
             list.addLast(i);
         }
 
         for (int i = 0; i < 200; i += 1) {
             assertThat(list.get(i)).isEqualTo(i);
         }
-    }*/
+    }
 }