泛型数组

1. 让我们的数据结构可以放置"任何"数据类型
2. 不可以是基本数据类型,只能是类对象

boolean,byte,char,short,int,long,float,double

3. 每个基本数据类型都有对应的包装类

Boolean,Byte ,Char,Short,Int,Long,Float,Double

Array类

package com.company;


public class Array<E> {
    private E[] data;
    private int size;
    //构造函数,传入数组的容量capacity构造Array
    public  Array(int capacity){
        data = (E[]) new Object[capacity];
        size = 0;
    }
    //无参数的构造函数,默认数组的容量capacity=10
    public Array(){
        this(10);

    }

    //获取数组中元素的个数
    public int getSize(){
        return size;
    }
    //获取数组的容量
    public int getCapacity(){
        return data.length;
    }
    //判断数组是否为空
    public boolean isEmpty(){
        return size == 0;
    }
    //向所有元素后添加一个新元素
//    public void addLast(int e){
//        if(size==data.length){
//            throw new IllegalArgumentException("AddLast failed.Array is full.");
//        }
//        data[size] = e;
//        size ++;
//    }
    public void addLast(E e){
        add(size,e);
    }
    //向第一个元素前添加一个新的元素
    public void addFirst(E e){
        add(0,e);
    }
//在第index个位置插入一个新元素e
public void add(int index,E e){
    if (size == data.length){
        throw new IllegalArgumentException("Add failed.Array is full");
    }
    if (index<0||index>size){
        throw  new IllegalArgumentException("Add failed.Require index >=0 and index<=size");
    }
    for (int i =size-1;i >=index;i--){
        data[i+1]=data[i];
    }
    data[index]=e;
    size++;
}
    //获取index索引位置的元素
    public E get(int index){
        if(index <0 || index >= size){
            throw new IllegalArgumentException("Get failed. Index is illegal.");
        }
        return data[index];
    }

    //修改index索引位置的元素为e
    public void set(int index, E e){
        if(index <0 || index >= size)
            throw new IllegalArgumentException("Get failed. Index is illegal");
        data[index]=e;
    }
    //查找数组中是否有元素e
    public boolean contains(E e){
        for (int i =0;i<size;i++){
            if(data[i].equals(e))
                return true;
        }
        return false;
    }
    // 查找数组中元素e所在的索引,如果不存在元素e,则返回-1
    public int find(E e){
        for(int i = 0;i<size;i++){
            if(data[i].equals(e)){
                return i;
            }

        }
        return -1;
    }
    //从数组中删除index位置的元素,返回删除元素
    public E remove(int index){
        if (index<0||index>=size){
            throw new IllegalArgumentException("Remove failed.Index is illegal");
        }
        E ret = data[index];
        for(int i = index+1;i<size;i++){
            data[i-1]=data[i];

        }
        size--;
       // data[size] = null;
        return  ret;
    }
    //从数组中删除第一个元素,返回删除的元素
    public E removeFirst(){
        return remove(0);
    }
    //从数组中删除最后一个元素,返回删除的元素
    public E removeLast(){
        return remove(size-1);
    }
    //从数组中删除元素e
    public void removeElement(E e)
    {
        int index = find(e);
        if(index !=-1){
            remove(index);
        }
    }    @Override
    public String toString() {
        StringBuilder res = new StringBuilder();
        res.append(String.format("Array: size = %d,capacity = %d\n", size, data.length));
        res.append('[');
        for (int i = 0;i<size;i++){
            res.append(data[i]);
            if(i!= size-1){
                res.append(",");
            }
        }
        res.append("]");
        return res.toString();
    }
}

Main类

package com.company;

public class Main {
	public static void main(String[] args) {
		Array<Integer> arr = new Array<>(20);
		//Array<Integer> arr = new Array<Integer>(20);
		for(int i = 0;i<10;i++)
			arr.addLast(i);
		System.out.println(arr);

		arr.add(1,100);
		System.out.println(arr);

		arr.addFirst(-1);
		System.out.println(arr);

		arr.remove(2);
		System.out.println(arr);

		arr.removeElement(4);
		System.out.println(arr);

		arr.removeFirst();
		System.out.println(arr);
	}

}

Student类

package com.company;

public class Student {
    private String name;
    private int score;

    public Student(String studentName,int studentScore){
        name = studentName;
        score = studentScore;
    }
    @Override
    public String toString(){
        return String.format("Student(name: %s,score:%d",name,score);

    }

    public static void main(String[] args) {
        Array<Student> arr = new Array<>();
        arr.addLast(new Student("Alice",100));
        arr.addLast(new Student("Bob",66));
        arr.addLast(new Student("CharLie",88));
        System.out.println(arr);
    }
}

来源：CSDN

作者：记一世盛开的花

链接：https://blog.csdn.net/weixin_42913025/article/details/104656204