sort( r, lo, up )
     ArrayToSort r;
     int lo, up;

     {int i, j;
     while (up>lo)  {
          j = lo;
          for ( i=lo; i<up; i++ )
               if ( r[i].k > r[i+1].k ) {
                    exchange( r, i, i+1 );
                    j = i;}
          up = j;
          for ( i=up; i>lo; i-- )
               if ( r[i].k < r[i-1].k ) {
                    exchange( r, i, i-1 );
                    j = i;}
          lo = j;
          }
     }