c++ - 单排序链表 - 无限循环

Question

我正在使用单个链表，我想将它从较低的整数值到较高的整数值排序。我虽然有这个想法，但随后执行进入了无限循环，我看不清楚原因。这是我使用的代码的一部分:

class Node {

    int data;
    Node* next;

public:

    Node() { };
    void SetData(int aData) { data = aData; };
    void SetNext(Node* aNext) { next = aNext; };
    int Data() { return data; };
    Node* Next() { return next; };
};

class List {

    Node *head;

public:

    List() { head = NULL; };
    void Print();
    void Append(int data);
    void Delete(int data);
};

void List::Append(int data) {

    // Create a new node
    Node* newNode = new Node();
    newNode->SetData(data);
    newNode->SetNext(NULL);

    // Create a temp pointer
    Node *tmp = head;

    if ( tmp != NULL ) {
        // Nodes already present in the list
        // Parse to end of list anytime the next data has lower value
        while ( tmp->Next() != NULL && tmp->Next()->Data() <= newNode->Data() ) {
            tmp = tmp->Next();
        }

        // Point the lower value node to the new node
        tmp->SetNext(newNode);
        newNode->SetNext(tmp->Next());
    }
    else {
        // First node in the list
        head = newNode;
    }
}

void List::Print() {

    // Temp pointer
    Node *tmp = head;

    // No nodes
    if ( tmp == NULL ) {
        cout << "EMPTY" << endl;
        return;
    }

    // One node in the list
    if ( tmp->Next() == NULL ) {
        cout << tmp->Data();
        cout << " --> ";
        cout << "NULL" << endl;
    }
    else {
        // Parse and print the list
        do {
            cout << tmp->Data();
            cout << " --> ";
            tmp = tmp->Next();
        }
        while ( tmp != NULL );

        cout << "NULL" << endl;
    }
}

如果列表无限增加或者错误来自 Print 函数，我会感到困惑...抱歉，也许是虚拟错误。谢谢。

Answer 1

你的问题是这两行:

tmp->SetNext(newNode);
newNode->SetNext(tmp->Next());

你应该扭转他们。现在，你设置 tmp.next = newNode，然后 newNode.next = tmp.next (= newNode)，所以 newNode 指向它自己。然后遍历 newNode 导致无限循环。