h1:=callstock('if00',vthigh,6,-1);
h2:=callstock('if00',vthigh,6,-2);
h3:=callstock('if00',vthigh,6,-3);
.
.
.
.
h18:=callstock('if00',vthigh,6,-18);
h19:=callstock('if00',vthigh,6,-19);
h20:=callstock('if00',vthigh,6,-20);
variable:maxbuy=0;
max20:=max(h1,max(h2,max(h3...........,h20));
if buycond then maxbuy:=max20;