/*
 * BinarySearch.c
 *
 *  Created on: 2014年6月25日
 *      Author: wenbo
 */
#include <stdio.h>
int binarySearch(int arr[],int num,int length){
	int l = 0,u = length-1;
	int curr = 0;
	while(l<=u){
		curr = (u+l)/2;
		if(arr[curr]==num){
			printf("index of the num is:%d\n",curr);
			return curr;
		}
		if(arr[curr]<num){
			l = curr+1;
		}
		if(arr[curr]>num){
			u = curr-1;
		}
	}
	printf("can't find the number.\n");
	return -1;
}
int main(){
	int a[10] = {1,2,3,4,5,65,77,88,99,1001};
	binarySearch(a,1,10);
	binarySearch(a,65,10);
	binarySearch(a,1001,10);
	binarySearch(a,100,10);
	return 0;
}