主题：如何交替做标识

 a和b  不能共用相同的全局变量。

A:=IF((Z<LLV(Z,3)&&K<D&&S<M),1,2);
VARIABLE:flag=0;
A:=IF(c<o,1,2);
if A=1 and (flag=0 or flag=1) then BEGIN
 DRAWTEXT(1,H,'3'),COLORGREEN;
 flag:=-1;
end
if A=2 and (flag=0 or flag=-1) then BEGIN
DRAWTEXT(A=2,H,'X'),COLORGREEN;
 flag:=1;
end

B:=IF((Z>HHV(Z,2)&&K>D&&S>M),1,2);
VARIABLE:flag2=0;
B:=IF(c<o,1,2);
if b=1 and (flag2=0 or flag2=1) then BEGIN
 DRAWTEXT(1,l,'3'),COLORGRED;
 flag2:=-1;
end
if B=2 and (fla2g=0 or flag2=-1) then BEGIN
DRAWTEXT(b=2,l,'X'),COLORGRED;
 flag2:=1;
end