一步一步学习java数组学习(二分搜索)

public class TestSearch{
public static void main(String[] args){
int[] a = new int[]{1,3,6,8,9,10,12,18,20,38};
int x = 23;
if(binarySearch(a,x)>0){
System.out.println(binarySearch(a,x));
}else{
System.out.println("没有找到");
}
}
public static int binarySearch(int[] a,int x){
int startPos = 0;
int endPos = a.length;
int m = 0;
if(a.length==0)return -1;
while(startPos<=endPos){
m = (startPos + endPos)/2;
if(a[m]==x)return m;
if(a[m]<x)startPos = m + 1;
if(a[m]>x)endPos = m -1;
}
return -1;
}
}