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| 1 | +package Day_2017_2_20_DateStructure; |
| 2 | + |
| 3 | +public class ArrayList { |
| 4 | + |
| 5 | + |
| 6 | + private int size = 0; |
| 7 | + |
| 8 | + private Object[] elementData = new Object[10]; |
| 9 | + |
| 10 | + private Exception Exception; |
| 11 | + |
| 12 | + public void add(Object o){ |
| 13 | + if(size>elementData.length){ |
| 14 | + elementData = ArrayList.grow(elementData, 10); |
| 15 | + } |
| 16 | + for(int i = 0; i < elementData.length; i++){ |
| 17 | + if(null == elementData[i]){ |
| 18 | + elementData[i] = o; |
| 19 | + break; |
| 20 | + } |
| 21 | + } |
| 22 | + size++; |
| 23 | + } |
| 24 | + public void add(int index, Object o){ |
| 25 | + if(size>elementData.length){ |
| 26 | + elementData = ArrayList.grow(elementData, 10); |
| 27 | + } |
| 28 | + if(index<0){ |
| 29 | + System.out.println("Äú²åÈëµÄλÖÃÓÐÎó"); |
| 30 | + } |
| 31 | + int k = -1; |
| 32 | + for(int i = index; i < elementData.length; i++){ |
| 33 | + if(null==elementData[i]){ |
| 34 | + k = i-1; |
| 35 | + break; |
| 36 | + } |
| 37 | + } |
| 38 | + for(int i = k; i >= index;i--){ |
| 39 | + elementData[i+1] = elementData[i]; |
| 40 | + } |
| 41 | + elementData[index] = o; |
| 42 | + size++; |
| 43 | + } |
| 44 | + public Object get(int index){ |
| 45 | + return elementData[index]; |
| 46 | + } |
| 47 | + |
| 48 | + public Object remove(int index){ |
| 49 | + while(true){ |
| 50 | + elementData[index] = elementData[index+++1]; |
| 51 | + if(elementData[index]==null){ |
| 52 | + break; |
| 53 | + } |
| 54 | + } |
| 55 | + size--; |
| 56 | + return null; |
| 57 | + } |
| 58 | + public int size(){ |
| 59 | + return -1; |
| 60 | + } |
| 61 | + public void getElementData(){ |
| 62 | + for(int i = 0; i < elementData.length; i++){ |
| 63 | + System.out.println(elementData[i]); |
| 64 | + |
| 65 | + } |
| 66 | + } |
| 67 | + public static Object[] grow(Object[] elementData2, int size){ |
| 68 | + Object []target = new Object[elementData2.length+size]; |
| 69 | + System.arraycopy(elementData2, 0, target, 0, elementData2.length); |
| 70 | + return target; |
| 71 | + } |
| 72 | + |
| 73 | + public static void main(String[] args) { |
| 74 | + ArrayList a = new ArrayList(); |
| 75 | + a.add("a"); |
| 76 | + a.getElementData(); |
| 77 | + System.out.println(a.size); |
| 78 | + } |
| 79 | +} |
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