链表无法在next里添加新结点

Question

因为没有头结点，删除第一个结点很麻烦，但是保留头结点，在next又无法添加新结点，麻烦各位看一下应该如何修改

template <typename T > class Link {
private :
    node<T>* head;
    node<T>* rear;
public:
    Link() {
        node<T> *head = new node<T>;
        head = NULL;
        rear = head;
    }
        bool CreateLink(T k) {
        node<T> *value = new node<T>;
        value->data = k;
        value->next = NULL;
        rear->next = value;//在链表插入的时候，报错rear为nullptr无法添加
        rear = value;
        return true;
    }
}；

Answer 1

你要先判断head是否为空啊

template <typename T > class Link {
private :
    node<T>* head;
    node<T>* rear;
public:
    Link() {
        head = new node<T>;
        head->next = NULL;
        rear = head;
    }
        bool CreateLink(T k) {
        node<T> *value = new node<T>;
        value->data = k;
        value->next = NULL;
        rear->next = value;
        rear = value;
        return true;
    }
}；