#001_面向对象数组

data_structure/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>org.example</groupId>
+    <artifactId>data_structure</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+
+</project>

data_structure/src/main/java/sort/MyArr.java

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+package sort;
+
+import java.util.Arrays;
+
+/**
+ * @author Sawyer
+ * @date 2022/7/21
+ */
+public class MyArr {
+    private int[] elements;
+
+    public MyArr() {
+        elements = new int[0];
+    }
+
+    /**
+     * 获取数组长度
+     * @return 返回数组长度
+     */
+    public int size(){
+        return elements.length;
+    }
+
+    /**
+     * 往数组末尾添加一个元素
+     * @param element 新元素
+     */
+    public void add(int element){
+        int[] newArr = new int[elements.length+1];
+        System.arraycopy(elements, 0, newArr, 0, elements.length);
+        newArr[elements.length] = element;
+        elements = newArr;
+    }
+
+    /**
+     * 打印元素列表
+     */
+    public void show(){
+        System.out.println(Arrays.toString(elements));
+    }
+
+    /**
+     * 通过数组下标删除元素
+     * @param index 数组下标
+     */
+    public void remove(int index){
+        checkIndex(index);
+        int[] newArr = new int [elements.length-1];
+        for (int i = 0; i <newArr.length ; i++) {
+            if(i < index){
+                newArr[i] =elements[i];
+            }else {
+                newArr[i] = elements[i+1];
+            }
+        }
+        elements=newArr;
+    }
+
+    /**
+     * 通过下标获取元素
+     * @param index 数组下标
+     * @return 返回一个元素
+     */
+    public int getElement(int index){
+        checkIndex(index);
+        return elements[index];
+    }
+
+    /**
+     * 通过指定下标添加元素
+     * @param index 数组下标
+     * @param element 元素
+     */
+    public void insert(int index,int element){
+        checkIndex(index);
+        int[] newArr = new int[elements.length+1];
+        for (int i = 0; i <elements.length ; i++) {
+            if(i < index){
+                newArr[i] = elements[i];
+            }else {
+                newArr[i+1] = elements[i];
+            }
+        }
+        newArr[index] = element;
+        elements=newArr;
+    }
+
+
+
+    private void checkIndex(int index){
+        if(index <0 || index>elements.length){
+            throw new RuntimeException("下标越界");
+        }
+    }
+}

data_structure/src/main/java/sort/MyArrTest.java

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+package sort;
+
+/**
+ * @author Sawyer
+ * @date 2022/7/21
+ */
+public class MyArrTest {
+    public static void main(String[] args) {
+        MyArr myArr = new MyArr();
+        myArr.add(1);
+        myArr.add(2);
+        myArr.show();
+        int count = myArr.getElement(0);
+        System.out.println(count);
+        myArr.size();
+        myArr.insert(0,22);
+        myArr.show();
+        myArr.remove(0);
+        myArr.show();
+    }
+}