java 顺序表 增删改查

import java.util.Arrays; class MyArrayList { //属性 private int[] elem; private int usedSize;//有效数据的个数 private final int CAPACITY = 5;//容量 public MyArrayList() {//构造方法 this.elem = new int[CAPACITY]; this.usedSize = 0; } //方法 // 打印顺序表 public void display() { for (int i = 0; i < this.usedSize; i++) { System.out.print(this.elem[i] + " "); } System.out.println(); } private boolean isfull() { return this.elem.length == this.usedSize; } // 在 pos 位置新增元素 public void add(int pos, int data) { if (isfull()) { this.elem = Arrays.copyOf(this.elem, this.elem.length * 2); }//数组拷贝 2倍 if (pos < 0 || pos > this.usedSize) { System.out.println("该位置不合法"); } //挪数据 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 = this.usedSize; i >= 0; i--) { if (toFind == this.elem[i]) { return true; } } return false; } // 查找某个元素对应的位置 public int search(int toFind) { for (int i = 0; i < this.usedSize; i++) { if (this.elem[i] == toFind) { return i; } } return -1; } // 获取 pos 位置的元素 public int getPos(int pos) { if (pos < 0 || pos > usedSize) { return -1;//没有pos位置 } return this.elem[pos]; } // 给 pos 位置的元素设为 value public void setPos(int pos, int value) { this.elem[pos] = value; } //删除第一次出现的关键字key public void remove(int toremove) { int a = search(toremove); if (a == -1) { System.out.println("找不到要删除的数字"); } for (int i = a; 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() { this.usedSize = 0; } } public class Test2 { public static void main(String[] args) { MyArrayList myArrayList= new MyArrayList(); myArrayList.add(0,12); myArrayList.add(1,23); myArrayList.add(2,34); myArrayList.add(3,45); myArrayList.add(4,56); //myArrayList.add(5,90); int sum = myArrayList.search(90); System.out.println(sum); myArrayList.remove(23); //myArrayList.remove(6); myArrayList.display(); int L = myArrayList.size(); System.out.println(L); myArrayList.clear();//清空 myArrayList.display(); } } ========================================== 输出结果： -1 12 34 45 56 4