[数据结构与算法]实现对数组的增删改查（JAVA版本）

public class Array {
    public static void main(String[] args)throws Exception {
    //这里填写测试代码就行了
    CRUD a1 = new CRUD(2);
    a1.add(0,2);
    a1.add(1,2);
    a1.update(1,3)
   }
}
class CRUD{
    private int[] array ;
    private int size;
    public CRUD(int length){
        array = new int[length];
        size = 0;
    }
    public void add(int index , int element)throws Exception{
        if (index<0||index> size){
            throw new Exception("数组越界");
        }
        if (size == array.length){
            resize();
            System.out.println("数组发生扩容，当前大小为"+array.length);
        }
        for (int i = size-1; i >= index ; i--) {
            array[i+1] = array[i];
        }
        array[index] = element;
        size++;
    }
    
    public void resize(){
        int[] array = new int[size*3];
        System.arraycopy(this.array,0,array,0,this.array.length);
        this.array = array;
    }
    
    public void delete(int index)throws Exception{
        if (index<0||index>size){
            throw new Exception("数组越界");
        }
        for (int i = index; i <size ; i++) {
            array[i] = array[i+1];
        }
        size--;
    }
    
    public void update(int index,int element)throws Exception{
        if (index>size||index<0){
            throw new Exception("数组越界");
        }
        array[index] = element;
    }
    
    public void output(){
        System.out.print("当前数组是:");
        for (int i= 0;i<size;i++){
            System.out.print(array[i]+" ");
        }
        System.out.println();
    }


}