单链表插入
class A {

struct B {
C *m_function;
struct B *m_next;
};

static struct B *head;

public:
static void insert(C *f);
};

A::B *A::head;

void A::insert(C *f)
{
struct B *old=head;
head = new struct B;
head->C = f;
head->m_next = old;

}

C::C()
{

A::insert(this);
}

有段错误
[解决办法]
不知道你想要什么，你的代码也不全，我自己加了一下。自己看吧，只是编译可过，
是不是你想要的不知道。

class C;
class A 
{
struct B 
{
C *m_function;
struct B *m_next;
};
static struct B *head;
public:
static void insert(C *f);
};

class C
{
public:
C()
{
A::insert(this);
}
};

A::B *A::head;

void A::insert(C *f)
{
struct B *old=head;
head = new struct B;
head->m_function = f;
head->m_next = old;
}