C++指针无法返回值

Question

我正在尝试用 C++ 创建一个带有指针的链表结构。但似乎该节点未正确分配，并且我无法获得有关内部发生的情况的更多信息。

#include <iostream>
using namespace std;

struct LLNode{
    int value;
    LLNode* next = nullptr;
};

class LinkedList{
    private:
        int size;
        LLNode* head;
        LLNode* crr;

    public:
        // constructor
        LinkedList(){
            size = 0;
            head = nullptr;
            crr = nullptr;
        }

        /* create node with input value
         * link the node to the end of the list
        */
        int append(int value){
            LLNode* node = new LLNode; node->value = value;
            LLNode* current = head;

            // add as head node
            if(head == nullptr){
                head = node;
            }
            // add at the end of nodes
            else{
                while(current->next != nullptr){
                    current = current->next;
                }
                current->next = node;
            }
            size++;
            return current->next->value;
        }

int main(){
    LinkedList llist;

    cout << llist.append(100) << endl;

    return 0;
}

return current->next->value;

没有返回任何内容。可能是节点分配有问题？如果有的话怎么解决？

Answer 1

您的代码中存在一些错误：

#include <iostream>
using namespace std;

struct LLNode {
  int value;
  LLNode* next = nullptr;
};

class LinkedList {
private:
  int size;
  LLNode* head;
  LLNode* crr;

public:
  // Constructor
  LinkedList() {
    size = 0;
    head = nullptr;
    crr = nullptr;
  }

  //Create a node with the input value and link it to the end of the list

  int append(int value){ // Added missing closing bracket here
    LLNode* node = new LLNode;
    node->value = value;
    LLNode* current = head;

    // Add as head node
    if (head == nullptr) {
      head = node;
    } else { // Added missing else block here
      // Add at the end of nodes
      while (current->next != nullptr) {
        current = current->next;
      }
      current->next = node;
    }

    size++;
    return node->value; // Changed to return the value of the newly added node
  }
}; // Added missing closing bracket for the class definition

int main() {
  LinkedList llist;
  cout << llist.append(100) << endl;
  return 0;
}