二分查找算法

 

int search_bin(int * a, int key, int s,int t)
{
 int mid;
 while(s<=t)
 {
  mid=(s+t)/2;
  if(a[mid]==key)
   return mid;
  else
   if(a[mid]>key)
    t=mid-1;
   else
    s=mid+1;
 }
 return -1;
}