tree insert( key, t )
     typekey key[];
     tree t;
     {
     int i, indx, noteq;
     if ( t==NULL ) t = NewNode( key );

     else {    indx = noteq = 0;
          for (i=0; i<K; i++) {
               indx = indx << 1;
               if ( key[i] > t->k[i] ) indx++;
               if ( key[i] != t->k[i] ) noteq++;
               }
          if ( noteq )   t->p[indx] = insert( key, t->p[indx] );
          else Error; /*** Key already in table ***/
          }
     return( t );
     };