ArrayList

group11/1310368322/GitHub/src/ArrayList.java

@@ -0,0 +1,79 @@
+package Day_2017_2_20_DateStructure;
+
+public class ArrayList {
+
+
+	private int size = 0;
+
+	private Object[] elementData = new Object[10];
+
+	private Exception Exception;
+
+	public void add(Object o){
+		if(size>elementData.length){
+			elementData = ArrayList.grow(elementData, 10);
+		}
+		for(int i = 0; i < elementData.length; i++){
+			if(null == elementData[i]){
+				elementData[i] = o; 
+				break;
+			}
+		}
+		size++;
+	}
+	public void add(int index, Object o){
+		if(size>elementData.length){
+			elementData = ArrayList.grow(elementData, 10);
+		}
+		if(index<0){
+			System.out.println("Äú²åÈëµÄλÖÃÓÐÎó");	
+		}
+		int k = -1;
+		for(int i = index; i < elementData.length; i++){
+			if(null==elementData[i]){
+				k = i-1;
+				break;
+			}
+		}
+		for(int i = k; i >= index;i--){
+			elementData[i+1] = elementData[i];
+		}
+		elementData[index] = o;
+		size++;
+	}
+	public Object get(int index){
+		return elementData[index];
+	}
+
+	public Object remove(int index){
+		while(true){
+			elementData[index] = elementData[index+++1];
+			if(elementData[index]==null){
+				break;
+			}
+		}
+		size--;
+		return null;
+	}
+	public int size(){
+		return -1;
+	}
+	public void getElementData(){
+		for(int i = 0; i < elementData.length; i++){
+			System.out.println(elementData[i]);
+
+		}
+	}
+	public static Object[] grow(Object[] elementData2, int size){
+		Object []target = new Object[elementData2.length+size];
+		System.arraycopy(elementData2, 0, target, 0, elementData2.length);
+		return target;
+	}
+
+	public static void main(String[] args) {
+		ArrayList a = new ArrayList();
+		a.add("a");
+		a.getElementData();
+		System.out.println(a.size);
+	}
+}