实现数组_1_增删改查

数组的增删改查

package com.company;

/**
 * @program: Array
 * @description: 数组
 * @author: Gu
 * @create: 2019-04-10 22:03
 **/

public class Array {

    private int[] data;
    private int size;

    //初始化
    public Array(int capacity) {
        data = new int[capacity];
        size = 0;
    }

    //无参构造函数默认最大容量为10
    public Array() {
        this(10);
    }

    //数组长度
    public int length() {
        return data.length;
    }

    //数组元素个数
    public int getSize() {
        return size;
    }

    //数组是否为空
    public boolean isEmpty() {
        return size == 0;
    }
    //向数组指定位置中添加元素
    public void add(int index, int element) {
        if (index >= data.length || index < 0) {
            throw new IllegalArgumentException("[数组索引非法]");
        }

        if (size >= data.length) {
            throw new IndexOutOfBoundsException("[数组已达到最大容量]");
        }

        for (int i = size - 1; i >= index; i--) {
            data[i + 1] = data[i];
        }
        data[index] = element;
        size++;
    }

    //向数组第一个索引添加元素
    public void addFirst(int element) {
        add(0, element);
    }

    //数组末尾添加元素
    public void addLast(int element) {
        add(size, element);
    }

    //根据index查找指定元素
    public int get(int index) {
        if (index < 0 || index >= size) {
            throw new IllegalArgumentException("[数组索引非法]");
        }
        return data[index];
    }

    //查找数组是否包含指定元素
    public boolean contains(int element) {
        for (int value : data) {
            if (value == element) {
                return true;
            }
        }
        return false;
    }

    //返回指定元素的索引
    public int find(int element) {
        for (int i = 0; i < size; i++) {
            if (data[i] == element) {
                return i;
            }
        }
        return -1;
    }


    //修改数组元素
    public void set(int index, int element) {
        if (index < 0 || index >= size) {
            throw new IllegalArgumentException("[数组索引非法]");
        }
        data[index] = element;
    }

    //删除指定元素
    public void delete(int element) {
        int index = find(element);
        if (index == -1) {
            throw new IllegalArgumentException("[数组没有该元素]");
        }
        remove(index);
    }

    //根据索引删除元素
    public int remove(int index) {
        if (index < 0 || index >= size) {
            throw new IllegalArgumentException("[数组索引非法]");
        }
        int res = data[index];
        for (int i = index + 1; i < size; i++) {
            data[i - 1] = data[i];
        }
        size = size - 1;
        return res;
    }

    //删除第一个
    public int removeFirst() {
        return remove(0);
    }

    //删除最后一个
    public int removeLast() {
        return remove(size - 1);
    }

    //打印数组相关信息
    @Override
    public String toString() {
        StringBuffer stringBuffer = new StringBuffer();
        stringBuffer.append(String.format("数组的size : %d, 数组的capacity : %d \n", size, data.length));
        stringBuffer.append("[");
        for (int i = 0; i < size; i++) {
            stringBuffer.append(data[i]);
            if (i == size - 1) {
                stringBuffer.append("]");
                break;
            }
            stringBuffer.append(",");
        }
        return stringBuffer.toString();
    }

}

测试类

public class Main {

    public static void main(String[] args) {

        Array arr = new Array(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);
        // [-1, 0, 100, 1, 2, 3, 4, 5, 6, 7, 8, 9]

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

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

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