用C++中的冒泡排序排序链接列表

Question

我一直在尝试使用交换函数对双向链表进行冒泡排序。我的问题是交换功能交换指针，而不仅仅是数据？我的代码告诉我它只交换数据而不是指针。有什么办法有效地交换链接列表上的指针？请向我展示代码，因为我在编码方面很缺乏经验，并且在其他答案中我不了解其他代码。

void sortPoly(PolyNode* a) 
{ 
    PolyNode* head =a; 
    PolyNode* current = head; 
    PolyNode* current_next = current->next; 


    int len =Polylength(current); 

    if(len ==1 || len ==0) 
    { 
     return; 
    } 

for(int i =0; i < len; i++) 
{ 
    for (int j =0; j< len -i; j++) 
    { 
     int sum = current->expx + current->expy; 
     cout << "sum=" << sum << endl; 
     int next_sum = current_next->expx + current_next->expy; 
     cout << "\t nextsum=" << next_sum << endl; 

     if(sum < next_sum) 
     { 
      cout << "current=" << current->coef << "expx = " << current->expx << "expy=" << current->expy << endl; 
      cout << "current_next=" << current_next->coef << "expx = " << current_next->expx << "expy=" << current_next->expy << endl; 

      std:: swap(current, current_next); 
      cout << endl; 
      cout << "swapped" << endl; 

      cout << "current=" << current->coef << "expx = " << current->expx << "expy=" << current->expy << endl; 
      cout << "current_next=" << current_next->coef << "expx = " << current_next->expx << "expy=" << current_next->expy << endl; 

      cout << "current=" << current->coef << "expx = " << current->expx << "expy=" << current->expy << endl; 
      cout << "current_next=" << current_next->coef << "expx = " << current_next->expx << "expy=" << current_next->expy << endl; 

     current = current->next; 

     current_next = current->next->next; 
     cout << "current=" << current->coef << "expx = " << current->expx << "expy=" << current->expy << endl; 
     cout << "current_next=" << current_next->coef << "expx = " << current_next->expx << "expy=" << current_next->expy << endl; 
    } 
    } 

} 

这是我的结构：

struct PolyNode 
    { 
     int coef; 
     int expx; 
     int expy; 
     PolyNode* prev; 
     PolyNode* next; 
    }; 

请找到下面我的Mac终端上的回应。

Answer 1

我想你可能在交换功能方面有问题。我不认为std :: swap可以交换prev和next引用。可以肯定的是，你可以实现你自己的交换。我会用这个功能来做到这一点。

void swap(PolyNode* node1, PolyNode* node2){ 
PolyNode* prev = node1->prev; 
PolyNode* next = node2->next; 
if (prev) 
    prev->next = node2; 
if (next) 
    next->prev = node1; 

node1->next = next; 
node1->prev = node2; 

node2->prev = prev; 
node2->next = node1; 
} 

btw，你必须移动迭代if。

current = current->next; 
current_next = current->next->next; 

部分必须是出于if