二分法查找

package cn.cp;
//二分查找的前提是：数组有序
//注意：mid的动态变化，否则出错！！！
public class BiSearch {
public static void main(String[] args) {
new BiSearch().biFind(new int []{1,2,3,4,5,6,7},3);
}
public void biFind(int arr[],int y){
int start=0;
int end=arr.length-1;
int mid=(start+end)/2;

while(start<=end){
if(y==arr[mid]){
System.out.println("查找成功，其下标为"+mid);
break;
}
if(y>arr[mid]){
start=mid+1;
mid=(start+end)/2;
}
if(y<arr[mid]){
end=mid-1;
mid=(start+end)/2;
}
if(start>end){
System.out.println("查找失败");

}
}
}
}