尝试删除所选节点的双向链表

我试图使用双向链表并从文本文件中读入以创建非常基本的缓存。目前缓存容量为 5，我从 txt 文件中读取了 20 个值 1-20。当我尝试删除头部然后打印链表时，它会打印 0,2,3-20，因此将 1 替换为 0。据我了解，我需要创建一个临时节点来设置为头部值，然后将头部指向下一个节点，最后删除临时节点，这就是我所做的，但我显然错过了一些重要的东西。

int main(int argc, char** argv) {
node* head;
node* tail;
node* n;
int capacity = 5; 
int size = 0;
std::string fileName;   
std::ifstream inFile;
int start_block, num_blocks, ignore, req_num;
std::cout << "Project 3 milestone: LRU" << std::endl;
std::cout << "Enter filename: " << std::endl;
std::cin >> fileName;

inFile.open(fileName.c_str(), std::ifstream::in);
if (!inFile)    {
    std::cerr << "Cannot open file!  " << fileName << std::endl;
}
while(inFile.is_open()) {
    inFile >> start_block >> num_blocks >> ignore >> req_num;
    n = new node;
    n->data = start_block;
    n->prev = NULL; // 1st node
    head = n;
    tail = n;
    size++;
    while(!inFile.eof())    {
        inFile >> start_block >> num_blocks >> ignore >> req_num;
        n = new node;
        n->data = start_block;
        n->prev = tail;
        tail->next = n;
        tail = n;
        size++;
        //std::cout << start_block << " " << num_blocks << " " << ignore << " " << req_num << std::endl;    
        if  (size == capacity)  {
            cout << "Reached capacity:" << capacity << endl;
            // this is where I would delete the head node
        }   
    }           
    inFile.close();
}
PrintForward(head);
//PrintReverse(tail);
SearchRecursive(head,18);
DeleteHead(head, tail);
PrintForward(head);
//DeleteHead(head, tail);
//PrintForward(head);
return 0;
}
void SearchRecursive(node* ptr, int searchValue)    {
if(ptr == NULL) {   // if we pssed through list and didnt find value
    cout << searchValue << " was NOT found in the listn";
}       
else if (ptr->data == searchValue)  {   // if we DID find it
    cout << searchValue << " IS in the list!n";
}
else    {
    SearchRecursive(ptr->next, searchValue);    // else search recursively
}
}
void DeleteHead(node* head, node* tail) {
if (head == tail)   {   // if only 1 element
    cout << "Only 1 element here" << endl;
    delete head;
    head = NULL;
    tail = NULL;
}
else    {
    cout << "More than 1 element here" << endl;
    node *temp = head;
    head = head->next;
    delete temp;
}
}

编辑：我改进了SearchRecursive功能，现在可以删除除头部和尾部之外的节点。这是我正在使用的：

void SearchRecursive(node* ptr, int searchValue)    {
if(ptr == NULL) {   // if we pssed through list and didnt find value
    cout << searchValue << " was NOT found in the listn";
}       
else if (ptr->data == searchValue)  {   // if we DID find it
    cout << searchValue << " IS in the list!n";
    ptr->prev->next = ptr->next;
    ptr->next->prev = ptr->prev;
    delete ptr;
}
else    {
    SearchRecursive(ptr->next, searchValue);    // else search recursively
}
}