bsearch

http://www.programmer-club.com.tw/ShowSameTitleN/evc/1937.html

[code]
void * __cdecl bsearch ( const void *key, const void *base, size_t num, size_t width, int (__cdecl *compare)(const void *, const void *) );
[/code]

[code]
void * __cdecl bsearch ( const void *key, const void *base, size_t num, size_t width, int (__cdecl *compare)(const void *, const void *) )
{
     char *lo = (char *)base;
     char *hi = (char *)base + (num - 1) * width;
     char *mid;
     unsigned int half;
     int result;

     while (lo <= hi)
     if (half = num / 2)
     {
     mid = lo + (num & 1 ? half : (half - 1)) * width;
     if (!(result = (*compare)(key,mid)))
     return(mid);
     else if (result < 0)
     {
     hi = mid - width;
     num = num & 1 ? half : half-1;
     }
     else {
     lo = mid + width;
     num = half;
     }
     }
     else if (num)
     return((*compare)(key,lo) ? NULL : lo);
     else
     break;

     return(NULL);
}
[/code]