**First, describe**

This paper analyzes and compares the binary search algorithm of JDK and the common binary search algorithm written by itself, uses bits unsigned right shift to replace the 2 operation, and uses the method of generating random number to produce a range of random number array, and calls the sort () static method of the arrays class to sort the array of int type.

math.random () Usage: Generates a random number between [0,1] (Note that you can take 0, not 1), this random number is a double type, to return the formula for a specified range of random numbers, such as an integer between [M,n]:(int) (Math.random () * (m-n+1) +m)

**Second, the source code**

<span style= "FONT-SIZE:18PX;" >package tong.yue.sort;import Java.awt.renderinghints.key;import java.util.arrays;/** * The comparison between the binary search algorithm and the common binary search algorithm written by the JDK * @author Administrator * */public class BinarySearch {public static void main (string[] args) {//Call the Randomintegerarray () method, randomly generate an array of 25 numbers int[] Valueresult = Randomintegerarray (25);//Call the sort () static method of the arrays class, Sort the above array (binary lookup can only improve search efficiency for already sorted arrays) Arrays.sort (Valueresult); System.out.print ("The result after sorting is:"); Printarrayline (Valueresult); For example I want to find the position of this number 20 int key = 20; Call common binary lookup algorithm int index = BinarySearch (Valueresult,key); SYSTEM.OUT.PRINTLN ("Common binary lookup algorithm results:" +key+ "in the array subscript is:" +index); Call the JDK's own binary lookup algorithm index = BINARYSEARCHJDK (Valueresult,key); System.out.println ("The JDK's own binary lookup algorithm results:" +key+ "in the array subscript is:" +index);} /* * The following methods are responsible for generating an array of n random numbers, and the range of random numbers is 0-49 */public static int[] Randomintegerarray (int n)//Returns an array of integer objects consisting of n random numbers { int[] value = new Int[n]; for (int i=0; i<value.length; i++) value[i]=new Integer ((int) (Math.random () *50);//Generates aA random number of 0-49 return value; Returns the array reference}/** * Normal binary lookup method, find the keyword to return the array subscript position of the keyword, can not find the keyword returned-1 */public static int binarysearch (int[] arr,int value) {// Binary lookup int min =0;int max = Arr.length-1;int mid = (Min+max)/2;while (arr[mid]!=value) {if (arr[mid]>value) {max = mid-1;} else if (arr[mid]<value) {min = mid+1;} if (Min>max) {return-1;} Mid = (max+min)/2;} return mid;} /* * The binary search method with the JDK, find the keyword to return the array subscript location of the keyword, the keyword is not found to return a negative number associated with the last find location */public static int binarysearchjdk (int[] Arr,int Value) {//The JDK itself comes with a binary lookup int min =0;int max = Arr.length-1;while (Min<=max) {//with unsigned Right shift one bit, which can be represented by 2int mid = (Min+max) >& Gt;>1;int Midvalue = arr[mid];if (midvalue>value) {max = mid-1;} else if (arr[mid]<value) {min = mid+1;} Else{return Mid;}} Returns a negative number that is related to the final position if not found-(min+1);} private static void Printarrayline (int[] arr) {//looping the values in the Print group, not printing 10 numbers on line wrap for (int i = 0; i < arr.length; i++) {if (i%10==0 ) {System.out.println ();} System.out.print (Arr[i] + "");} System.out.println ();}} </span>

**iii. Results of Operation**

A comparison of the binary search algorithm with the JDK and the common binary search algorithm written by itself (Java Binary Lookup source code)