二分查找算法

package com.gg.test;

public class BinarySearch{
	public static void main(String[] args){
		int[] a={1,2,3,4,5,6,7,8,9,10};
		int i =7;
		BinarySearch bs = new BinarySearch();
		System.out.println("所处位置: "+bs.find(a,i));
	}

	public int find(int[] a,int searchKey){
		int lowerBound =0;	//最低限度
		int upperBound =a.length-1; //最高限度,从0开始,数组长度a.length-1
		int curIn;

		while(true){ //死循环
			curIn = (lowerBound+upperBound)/2; //二分查找
			if(a[curIn]==searchKey){
				return curIn;
			}else if(lowerBound>upperBound){ //数组最短长度返回-1
				return -1;
			}else{
				if(a[curIn]<searchKey){
					lowerBound = curIn+1;
				}else{
					upperBound = curIn-1;
				}
			}
		
		}

	}
}