package com.array;
import java.util.Arrays;
public class twoArraytest {

public  static void show(int[][] arr){
  for(int i=0;i<arr.length;i++)
      for(int j=0;j<arr[i].length;j++)
        System.out.println(arr[i][j]);

}

     public static void main(String[] args) {
         int[][] arr=new  int[3][0];
         //1
         int a1[]=new int[]{1,2,3,4};
         //2
         int a2[]={1,2,3,4};
        // int [3] a3={1,3,4};
         //3
         int a3[];//申请一个句柄不能带参数
        // int [2] a3;报错
         a3=new int[4];

    //比较
         boolean b1=Arrays.equals(a1,a2);
     //复制
         int[] a5,a6 ;
         a5=Arrays.copyOf(a2, a2.length);
         a6=Arrays.copyOfRange(a2,2,3);//3
         System.out.println("a5"+Arrays.toString(a5));
         System.out.println("a6"+Arrays.toString(a6));
         System.out.println(b1);
    //二分法查找  查找一定要先排序    
         int []  a7=new int[]{1,2,5,3,4,8};
          Arrays.sort(a7);
        int a8=  Arrays.binarySearch(a7, 3);
        System.out.println(Arrays.toString(a7));
          System.out.println("Search three" + "　"+a8);

        //二维数组
         int  arr1[][]  ;
         arr1=new int[3][];
         int    arr2[][];
         arr1=new  int[4][5];
         int  arr3[][];
         //arr3=new  int[][5];行元素必须有值
         arr3=new int[][]{{1},{2},{3}};
         //arr3=new int[4][]{{1},{2},{3}};如果利用初始化列表就不用利用维度
         int[][] a = new int[][]{{1},{2},{3}};
         show(arr3);
         System.out.println("比较");
         //Arrays没有二维比较方法 只有利用重新函数来实现
        boolean b= Arrays.equals(a, arr3);
        System.out.println(b);

    }

}