Fixed bug in DynamicArray last element - credit goes to Andre Luis Gomes

rasmus4200 · Mar 23, 2020 · f1fa7e5 · f1fa7e5
1 parent 6178112
commit f1fa7e5
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Showing 2 changed files with 9 additions and 25 deletions.
diff --git a/src/main/java/datastructures/DynamicArray.java b/src/main/java/datastructures/DynamicArray.java
@@ -94,12 +94,16 @@ public void delete(int index) {
         for (int j = index; j < size - 1; j++) {
             data[j] = data[j + 1];
         }
-        size--;
 
-        // Clear if last element in array
-        if (index == size) {
+        // Clear last element of array
+
+        if (index == size) { // index is last element
             data[index] = null;
+        } else {
+            data[size - 1] = null; // index not last element
         }
+
+        size--;
     }
 
     public boolean isEmpty() {

diff --git a/src/test/java/datastructures/DynamicArrayTest.java b/src/test/java/datastructures/DynamicArrayTest.java
@@ -45,6 +45,7 @@ public void DeleteFirst() {
         Assert.assertEquals(2, array.size());
         Assert.assertEquals("b", array.get(0));
         Assert.assertEquals("c", array.get(1));
+        Assert.assertEquals(null, array.get(2));
     }
 
     @Test
@@ -58,6 +59,7 @@ public void DeleteMiddle() {
         Assert.assertEquals(2, array.size());
         Assert.assertEquals("a", array.get(0));
         Assert.assertEquals("c", array.get(1));
+        Assert.assertEquals(null, array.get(2));
     }
 
     @Test
@@ -74,28 +76,6 @@ public void DeleteLast() {
         Assert.assertEquals(null, array.get(2));
     }
 
-    @Test
-    public void DeleteLastArraySize1() {
-        array.add("a");
-
-        array.delete(0);
-
-        Assert.assertEquals(0, array.size());
-        Assert.assertEquals(null, array.get(0));
-    }
-
-    @Test
-    public void DeleteLastArraySize2() {
-        array.add("a");
-        array.add("b");
-
-        array.delete(1);
-
-        Assert.assertEquals(1, array.size());
-        Assert.assertEquals("a", array.get(0));
-        Assert.assertEquals(null, array.get(1));
-    }
-
     @Test
     public void isEmpty() {
         Assert.assertTrue(array.isEmpty());