带头结点的链栈

typedef struct SNode {
	int data;
	SNode *next;
}SNode;
typedef struct LStack {
	SNode *top;
}LStack;

void initLStack(LStack &S) {
	S.top = new SNode;
	S.top->data = NULL;
	S.top->next = NULL;
	return;
}
bool isEmptyLStack(LStack S) {
	if (S.top->next)
		return false;
	else
		return true;
}
void pushLStack(LStack &S,int e) {
	SNode* newNode = new SNode;
	newNode->data = e;
	newNode->next = S.top->next;
	S.top->next = newNode;
	S.top->data++;
	return;
}
void setLStack(LStack &S) {
	int i;
	while (cin >> i) {
		if (i == '#')break;
		pushLStack(S, (int)i);
	}
	return;
}
int popLStack(LStack &S) {
	int e;
	if (isEmptyLStack(S)) {
		cout << "Error: empty pop!" << endl;
		e = NULL;
		return e;
	}
	SNode* delNode = S.top->next;
	S.top->next = delNode->next;
	e = delNode->data;
	delete delNode;
	S.top->data--;
	return e;
}
int getLStackSize(LStack S) {
	return S.top->data;
}
void showLStack(LStack S) {
	if (isEmptyLStack(S)) {
		cout << "Empty!" << endl;
		return;
	}
	SNode *showNode = S.top->next;
	while (showNode) {
		cout << showNode->data << " ";
		showNode = showNode->next;
	}
	cout << endl;
	return;
}