我试图创建一个变量,它是节点指针的别名。

node* _p = &p;

&

node* &_p = p;

每当我试图调用一个类函数(即_p->getdata())或甚至引用时,都会使用别名(如果(_p==NULL)),我会得到一个错误,该错误表示:

error: expected primary-expression before ‘;’ token
             node* newnode = _p;

我也试过把*或&在我呼叫它之前,但这没有帮助。

注意:我使用g编译++

一个最小、完整且可验证的示例(我认为): 错误发生在list类的insert函数内。。。

class node{
private:
    int data;
    node* next;
    int mark;
public:
    node(int d = 0, node* n = NULL){
        data = d;
        next = n;
        mark = 0;
    }
    int getdata(){return data;}
    node* getnext(){return next;}
    int getmark(){return mark;}
    void setdata(int x){data = x;}
    void setnext(node* x){next = x;}
    void setmark(int x){mark = x;}
};
class list{
private:
    node* L1; //head pointers to list1, list2, and freelist.
    node* L2;
    node* free;
    node* front;
public:
    list(){
        front = new node();  //generate free list (empty)
        free = front;
        L1 = NULL;
        L2 = NULL;
        node* p = free;
        for (int i = 1; i < 10; i++){
            p -> setnext(new node());
            p = p -> getnext();
        }
        delete p;
    }

    void insert(int a, int x){
        if (free == NULL) {
            cout << a << " is full. can't insert " << x << " into the list." << endl;
            return;
        }
        if (a == 1) node* &list = L1;
        else if (a == 2) node* &list = L2;
        else {
            cout << "not a valid list";
            return;
        }
        if (list == NULL){
            list = free;
            free = free -> getnext();
            list -> setdata(x);
            list -> setnext(NULL);
        }
        else {
            node* p = list;
            while (p -> getnext() != NULL) {p = p -> getnext();}
            p -> setnext(free);
            free = free -> getnext();
            p -> getnext() -> setnext(NULL);
            p -> getnext() -> setdata(x);
        }
    }
};