Java实现Vector主要操作

Posted 2020-10-07

  1 package Eric.ADT;
  2 
  3 import org.junit.Test;
  4 
  5 /**
  6  * <p>
  7  * Title:MyVector
  8  * </p>
  9  * <p>
 10  * Description:Implement vector by java
 11  * </p>
 12  * <p>
 13  * Location:Frostburg
 14  * </p>
 15  * 
 16  * @author: Eric.Chen
 17  * @date:2017年9月17日上午9:15:19
 18  */
 19 public class MyVector implements JavaVector, Cloneable {
 20     private static final int InicialCapacity = 100;
 21     private int minCapacity;
 22     private Object[] elementData;
 23     private int size;
 24 
 25     public MyVector() {
 26         elementData = new Object[InicialCapacity];
 27         size = 0;
 28         minCapacity += elementData.length;//扩容时的增量
 29     }
 30 
 31     // 1.添加元素
 32     @Override
 33     public void append(Object element) {
 34         if (size == elementData.length) {
 35             ensureCapacity(InicialCapacity);
 36         } else {
 37             elementData[size] = element;
 38             size++;
 39         }
 40 
 41     }
 42 
 43     // 2.清空向量
 44     @Override
 45     public void clear() {
 46         int size = elementData.length;
 47         for (int i = 0; i < elementData.length; i++) {
 48             elementData[i] = (Integer) null;
 49             size--;
 50         }
 51 
 52     }
 53 
 54     // 3.判断向量中是否含有特定元素
 55     @Override
 56     public boolean contains(Object element) {
 57         for (int i = 0; i < elementData.length; i++) {
 58             if (element.equals(elementData[i]))
 59                 return true;
 60         }
 61         return false;
 62     }
 63 
 64     // 4.查找指定元素的角标
 65     @Override
 66     public Object elementAt(int index) {
 67         for (int i = 0; i < elementData.length; i++) {
 68             if (elementData[i].equals(elementData[index])) {
 69                 return elementData[i];
 70             }
 71         }
 72         return null;
 73     }
 74 
 75     // 5.查找指点角标对应的值
 76     @Override
 77     public int indexOf(Object element) {
 78         for (int i = 0; i < elementData.length; i++) {
 79             if (elementData[i].equals(element))
 80                 return i;
 81         }
 82         return -1;
 83     }
 84 
 85     // 6.判断向量是否为空
 86     @Override
 87     public boolean isEmpty() {
 88         if (size() == 0)
 89             return false;
 90         else
 91             return true;
 92     }
 93 
 94     // 7.删除指定角标的元素
 95     @Override
 96     public void removeAt(int index) {
 97         for (int i = index; i < elementData.length - 1; i++) {
 98             elementData[i] = elementData[i + 1];
 99         }
100         Object[] temp = new Object[elementData.length - 1];
101         for (int i = 0; i < elementData.length - 1; i++) {
102             temp[i] = elementData[i];
103         }
104         elementData = temp;
105 
106     }
107 
108     // 8.移除指定元素
109     @Override
110     public void remove(Object element) {
111         // TODO Auto-generated method stub
112         for (int i = 0; i < elementData.length; i++) {
113             if (element.equals(elementData[i])) {
114                 removeAt(i);
115             }
116         }
117 
118     }
119 
120     // 9.用指定的元素代替指定角标的值
121     @Override
122     public void replace(int index, Object element) {
123         // TODO Auto-generated method stub
124         elementData[index] = element;
125 
126     }
127 
128     // 10.返回向量中的元素个数，不包括null
129     @Override
130     public int size() {
131         int num = 0;
132         for (int i = 0; i < elementData.length; i++) {
133             if (elementData[i] != null) {
134                 num++;
135             }
136         }
137         return num;
138     }
139 
140     // 11.当数组长度不够时进行扩容
141     @Override
142 
143     public boolean ensureCapacity(int minCapacity) {
144         Object[] temp = new Object[elementData.length + minCapacity];
145         for (int i = 0; i < temp.length; i++) {
146             temp[i] = elementData[i];
147         }
148         elementData = temp;
149         return true;
150     }
151 
152     // 12.反转数组
153     @Override
154     public void reverse() {
155         Object[] data = new Object[elementData.length];
156         int j = data.length - 1;
157         for (int i = 0; i < size(); i++) {
158             data[j] = elementData[i];
159             j--;
160         }
161         elementData = data;
162     }
163 
164     // 13.克隆数组
165     @Override
166     public Object clone() {
167         Object[] cloneArray = new Object[size()];
168         for (int i = 0; i < size(); i++) {
169             cloneArray[i] = elementData[i];
170         }
171         return cloneArray;
172 
173     }
174 
175     // 14.移除指定区域的元素 包括开头，不包括结尾
176     @Override
177     public void removeRange(int fromIndex, int toIndex) {
178         Object[] temp = new Object[size() - (toIndex - fromIndex)];
179         int j = 0;
180         for (int i = 0; i < size(); i++) {
181 
182             if (i < fromIndex || i >= toIndex) {
183                 temp[j] = elementData[i];
184                 j++;
185             }
186         }
187 
188         elementData = temp;
189     }
190 
191     // 15.没看懂要干什么，哈哈哈
192     @Override
193     public void merge(MyVector vector2) {
194         // TODO Auto-generated method stub
195     }
196 
197     // 16.在指定位置插入指定元素
198     @Override
199     public void insertAt(int index, Object element) {
200         for (int i = size() - 1; i >= index; i--) {
201             elementData[i + 1] = elementData[i];
202         }
203         elementData[index] = element;
204         size++;
205     }
206 
207     // 17.将数组转化成字符串返回
208     @Override
209     public String toString() {
210         StringBuffer sb = new StringBuffer();
211         for (int i = 0; i < size(); i++) {
212             sb.append(elementData[i]);
213             sb.append(",");
214         }
215         String substring = sb.substring(0);
216         return substring;
217     }
218 
219     // 18.单元测试块
220     @Test
221     public void Test() {
222         append(20);
223         append(30);
224         append(40);
225         append(50);
226         append(60);
227         append(10);
228         append(70);
229         String strArray = toString();
230         System.out.println(strArray);
231     }
232 }