finish ArrayList\'s iterator method

BlankKelly · BlankKelly · commit 77e674606311 · 2017-02-25T20:03:08.000+08:00
diff --git a/group08/769638826/src/main/java/com/coding/basic/ArrayList.java b/group08/769638826/src/main/java/com/coding/basic/ArrayList.java
@@ -76,13 +76,15 @@ public int size() {
     }
 
     public Iterator iterator() {
-        return null;
+        return new ListIterator();
     }
 
     private class ListIterator implements Iterator{
+        int cursor;
+
         @Override
         public boolean hasNext() {
-            return size != 0;
+            return cursor != size;
         }
 
         public void remove(){
@@ -91,12 +93,19 @@ public void remove(){
 
         @Override
         public Object next() {
-            if(!hasNext()){
+            if(!hasNext()) {
                 throw new NoSuchElementException();
             }
 
-            //TODO
-            return null;
+            int i = cursor;
+            if (i >= size)
+                throw new NoSuchElementException();
+
+            Object[] elementData = ArrayList.this.elementData;
+
+            cursor = i + 1;
+
+            return elementData[i];
         }
     }
 }

Original file line number	Diff line number	Diff line change
`@@ -76,13 +76,15 @@ public int size() {`
`76`	`76`	`}`
`77`	`77`
`78`	`78`	`public Iterator iterator() {`
`79`		`- return null;`
	`79`	`+ return new ListIterator();`
`80`	`80`	`}`
`81`	`81`
`82`	`82`	`private class ListIterator implements Iterator{`
	`83`	`+ int cursor;`
	`84`	`+`
`83`	`85`	`@Override`
`84`	`86`	`public boolean hasNext() {`
`85`		`- return size != 0;`
	`87`	`+ return cursor != size;`
`86`	`88`	`}`
`87`	`89`
`88`	`90`	`public void remove(){`
`@@ -91,12 +93,19 @@ public void remove(){`
`91`	`93`
`92`	`94`	`@Override`
`93`	`95`	`public Object next() {`
`94`		`- if(!hasNext()){`
	`96`	`+ if(!hasNext()) {`
`95`	`97`	`throw new NoSuchElementException();`
`96`	`98`	`}`
`97`	`99`
`98`		`- //TODO`
`99`		`- return null;`
	`100`	`+ int i = cursor;`
	`101`	`+ if (i >= size)`
	`102`	`+ throw new NoSuchElementException();`
	`103`	`+`
	`104`	`+ Object[] elementData = ArrayList.this.elementData;`
	`105`	`+`
	`106`	`+ cursor = i + 1;`
	`107`	`+`
	`108`	`+ return elementData[i];`
`100`	`109`	`}`
`101`	`110`	`}`
`102`	`111`	`}`