实现底层基于数组的一个线性表：

1.首先列出线性表的功能(增、删、改、查) 使用接口来定义功能。

2.实现接口，实现线性表的功能

public interface Mylist1_2 {void add(Object element);void delete(Object element);void delete(int index);void updata(int index,Object newElement);boolean contain(Object target);Object at(int index);int Indexof(Object element);
}

public class MyArraryList1_2 implements Mylist1_2{private Object[] elements;private int size = 0;private int capacity = 10;public MyArraryList1_2(int capacity) {this.capacity = capacity;elements = new Object[capacity];}public MyArraryList1_2(){elements = new Object[capacity];}//扩容//1.首先考虑  当前数组的长度是否等于数组的容量 如果等于的话 需要进行扩容//2.需要把旧数组的元素搬过来  然后丢掉原来数组@Overridepublic void add(Object element) {if (size == capacity){capacity=capacity*2;Object[] newArr = new Object[capacity];for (int i = 0; i < size-1; i++) {newArr[i] = elements[i];}//丢掉旧的数组   把新数组的地址传给elementelements = newArr;}else {//如果不等于的话直接添加到数组里面elements[size++] = element;}}@Overridepublic void delete(Object element) {int index = Indexof(element);if (index>0){delete(index);}}@Overridepublic void delete(int index) {if (index < size || index > 0){for (int i = index; i < size-1; i++) {//将后面往前移elements[i] = elements[i+1];}size--;elements[size] = null;}}@Overridepublic void updata(int index, Object newElement) {elements[index] = newElement;}@Overridepublic boolean contain(Object target) {//如果大于0 说明数组中存在此元素return Indexof(target)>0;}@Overridepublic Object at(int index) {return elements[index];}@Overridepublic int Indexof(Object element) {for (int i = 0; i < size; i++) {if(elements[i].equals(element)) {return i;}}return -1;}@Overridepublic String toString() {StringBuilder sb = new StringBuilder("[");for (int i = 0; i < size; i++) {sb.append(elements[i]+(i==size-1?"":","));}sb.append("]");return sb.toString();}
}

import static org.junit.jupiter.api.Assertions.*;class MyArraryList1_2Test {@org.junit.jupiter.api.Testvoid add() {MyArraryList1_2 list = new MyArraryList1_2();list.add("nike");list.add("NB");list.add("anta");System.out.println(list);}@org.junit.jupiter.api.Testvoid delete() {}@org.junit.jupiter.api.Testvoid testDelete() {}@org.junit.jupiter.api.Testvoid updata() {}@org.junit.jupiter.api.Testvoid contain() {}@org.junit.jupiter.api.Testvoid at() {}}