12、自己实现的ArrayList

Bertha 。 2022-07-16 01:12 175阅读 0赞

1、自己实现的ArrayList的代码如下

package com.baowei.test;
    
    public class MyArrayList<E> {
    	// 表示当前的存储元素的大小
    	private int size = 0;
    	// 表示容量的大小
    	private int capacity = 10;
    	// 数值，用于保存数据
    	private E[] values = null;
    
    	// 无参构造函数
    	@SuppressWarnings("unchecked")
    	public MyArrayList() {
    		values = (E[]) new Object[capacity];
    	}
    
    	// 有参构造函数
    	@SuppressWarnings("unchecked")
    	public MyArrayList(int capacity) {
    		this.capacity = capacity;
    		values = (E[]) new Object[capacity];
    	}
    
    	public void add(E e) {
    		if (e == null) {
    			throw new RuntimeException("输入的元素为Null...");
    		}
    		if (size >= capacity) {
    			// 重新构造大小
    			enlargeCapacity();
    		}
    		// 放入元素
    		values[size] = e;
    		size++;
    	}
    
    	public E get(int index) {
    		if (index < 0 || index >= size) {
    			throw new RuntimeException("下标异常... ");
    		}
    		// 放入元素
    		return values[index];
    	}
    
    	public E remove(int index) {
    		if (index < 0 || index >= size) {
    			throw new RuntimeException("下标异常... ");
    		}
    
    		for (int i = index; i < size - 1; i++) {
    			values[i] = values[i + 1];
    		}
    		values[size - 1] = null;
    		size--;
    		return values[index];
    
    	}
    
    	@SuppressWarnings("unchecked")
    	private void enlargeCapacity() {
    		capacity = capacity * 2;
    		E[] tmpValues = (E[]) new Object[capacity];
    		System.arraycopy(values, 0, tmpValues, 0, size);
    		values = tmpValues;
    	}
    
    	public String toString() {
    		StringBuilder sb = new StringBuilder();
    		sb.append("[");
    		for (int i = 0; i < size; i++) {
    			sb.append(values[i]).append(",");
    		}
    		if (size > 0) {
    			sb.deleteCharAt(sb.length() - 1);
    		}
    		sb.append("]");
    		return sb.toString();
    	}
    
    	public static void main(String[] args) {
    		MyArrayList<String> myList = new MyArrayList<String>();
    		myList.add("0");
    		myList.add("1");
    		myList.add("2");
    		myList.add("3");
    		myList.add("4");
    		myList.add("5");
    		myList.add("6");
    		myList.add("7");
    		myList.add("8");
    		myList.remove(7);
    		System.out.println(myList.toString());
    	}
    }

2、参考的博客地址

[http://blog.csdn.net/fenglibing/article/details/14166011][http_blog.csdn.net_fenglibing_article_details_14166011]

[http_blog.csdn.net_fenglibing_article_details_14166011]: http://blog.csdn.net/fenglibing/article/details/14166011