#include <stdio.h>
int BinarySearch(int a[], int n, int key)
{  int low,high,mid;
   low=1; high=n;
   while(low<=high)
   {  mid=(low+high)/2;
if(key==a[mid]) return mid;
else if(key<a[mid]) high=mid-1;
else low=mid+1;
	}
	return 0;
}

void CreatSearchTable(int a[],int n)  /*創(chuàng)建查找表，且為遞增有序的*/
{ int i;
  printf("Input %d numbers:", n);
  for(i=1;i<=n;i++)
     scanf("%d",&a[i]);
}

main()
{int a[30], key;
  int n,loc;
  n=11;
  CreatSearchTable(a,n);
  printf("Input a number to search:");
  scanf("%d",&key);
  loc=BinarySearch(a,n,key);
  if(loc) printf("%d is found!! Position is %d!!\n",key,loc);
  else printf("%d  is not found!!!\n",key);
}