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作者：Mylvzi 

 文章主要内容：数据结构之顺序表的模拟实现 

 

/*** Created with IntelliJ IDEA.* Description:* User: 绿字* Date: 2023-10-12* Time: 8:53*/
import java.util.*;
/*** 顺序表详解*/
public class MyArrayList {private int[] elem;// 存放数据的数组private int usedSize;// 有效数据个数public static final int DEFAULT_SIZE = 10;// 初始化顺序表public MyArrayList() {this.elem = new int[DEFAULT_SIZE];}public MyArrayList(int ininCapacity) {// 自定义数组的大小this.elem = new int[ininCapacity];}// 打印顺序表public void display() {for (int i = 0; i <this.usedSize ; i++) {System.out.print(this.elem[i] +" ");}}// 添加数据  默认是在末尾添加public void add(int data) {// 满了要扩容if(isFull()) {this.elem = Arrays.copyOf(this.elem,2*this.elem.length);}this.elem[usedSize] = data;this.usedSize++;}// 判断是否已满public boolean isFull() {if(this.usedSize == this.elem.length) {return true;}return false;}// 在 pos 位置新增元素public void add(int pos, int data) {// pos位置要合法if(pos<0 || pos>this.usedSize) {throw new RuntimeException(pos+"位置不合法");}if(isFull()) {this.elem = Arrays.copyOf(this.elem,2*this.elem.length);}for (int i = this.usedSize-1; i >=pos ; i--) {this.elem[i+1] = this.elem[i];}this.elem[pos] = data;this.usedSize++;}// 判定是否包含某个元素public boolean contains(int toFind) {for (int i = 0; i <this.usedSize ; i++) {if(this.elem[i] == toFind) {return true;}}System.out.println("数组不包含该元素");return false;}// 查找某个元素对应的位置public int indexOf(int toFind) {for (int i = 0; i <this.usedSize ; i++) {if(this.elem[i] == toFind) {return i;}}System.out.println("数组不包含该元素");return -1;}// 检查pos位置是否合法private void checkPosLegal(int pos) {if(pos<0 || pos>=this.usedSize) {throw new posOutOfBoundException(pos+" 位置不合法");}}// 获取 pos 位置的元素public int get(int pos) {checkPosLegal(pos);return this.elem[pos];}// 给 pos 位置的元素设为 value  pos位置必须含有元素public void set(int pos, int value) {checkPosLegal(pos);this.elem[pos] = value;}//删除第一次出现的关键字keypublic void remove(int toRemove) {int index = indexOf(toRemove);for (int i = index; i <this.usedSize-1 ; i++) {this.elem[i] = this.elem[i+1];}this.usedSize--;}// 获取顺序表长度public int size() {return this.usedSize;}// 清空顺序表public void clear() {// 如果是引用类型所有的引用都要置空
//        for (int i = 0; i <this.usedSize; i++) {
//            this.elem[i] = null;
//        }this.usedSize = 0;}
}

/*** Created with IntelliJ IDEA.* Description:* User: 绿字* Date: 2023-10-12* Time: 10:49*/
public class posOutOfBoundException extends RuntimeException{public posOutOfBoundException() {}public posOutOfBoundException(String message) {super(message);}
}

/*** Created with IntelliJ IDEA.* Description:* User: 绿字* Date: 2023-10-12* Time: 9:02*/
public class Test1 {public static void main(String[] args) {MyArrayList myArrayList = new MyArrayList(5);myArrayList.add(1);myArrayList.add(2);myArrayList.add(3);myArrayList.add(4);
/*        System.out.println(myArrayList.size());myArrayList.remove(1);System.out.println(myArrayList.size());*/
//        myArrayList.add(100,99);
/*        myArrayList.set(0,999);myArrayList.remove(999);myArrayList.remove(2);myArrayList.remove(3);myArrayList.remove(4);myArrayList.remove(5);*//*        System.out.println(myArrayList.get(0));System.out.println(myArrayList.get(-1));System.out.println(myArrayList.get(999));*/
//        System.out.println(myArrayList.contains(2));
//        System.out.println(myArrayList.indexOf(2));
//
/*        myArrayList.add(0,999);myArrayList.add(0,999);myArrayList.add(0,999);myArrayList.add(0,999);myArrayList.add(0,999);*/
myArrayList.clear();myArrayList.display();}
}