search( key, t )
     typekey key[K];
     tree t;
     {
     int lev, i;
     for ( lev=0; t != NULL; lev=(lev+1)%K ) {
          for ( i=0; i<K && key[i]==t->k[i]; i++ );
          if ( i==K )    { found( t ); return; }
          if ( key[lev] > t->k[lev] ) t = t->right;
               else      t = t->left;
          }
     notfound( key );
     };