من خودم این طوری نوشتم
class variable:public leaf
{
static int i;
Expression s[9];
public:
variable(char *a,Expression &s2);
variable(char *a,int j);
Expression get_variable(int j);
virtual float value(){return 0;}
};
int variable::i=0;
variable::variable(char *a,Expression &s2)
{
while((a=="k+")&&(i<9))
{
s[i]=s2;
//i++;
}
}
variable::variable(char *a,int j)
{
while((a=="k-")&&(j>=0&&j<=i))
{
get_variable(j);
}
}
Expression variable::get_variable(int j)
{
return s[j];
}