c-Segfault插入到客户的链接列表中

Question

我想创建一个堆栈，但我想保留类似头指针的链表实现。我的意思是正面对反面。

void insertCustomer(CustomerPtr *headPtr, int id, char name[20], char surname[20]){
CustomerPtr newPtr = (CustomerPtr)malloc(sizeof(Customer));
newPtr->customerId = id;
strcpy(newPtr->customerName, name);
strcpy(newPtr->customerSurname, surname); 
CustomerPtr previousPtr, currentPtr;
previousPtr = NULL;
currentPtr = *headPtr;
while(currentPtr != NULL){
previousPtr = currentPtr;
currentPtr = currentPtr->next; 
}
if(previousPtr == NULL){  
*headPtr = newPtr;
} else{
previousPtr->next = newPtr;
} 

} 

我有一个分割错误。

Answer 1

您似乎忘记初始化newPtr->next了。通过malloc()分配的区域的初始值是不确定的，使用不确定的值会调用未定义的行为。

void insertCustomer(CustomerPtr *headPtr, int id, char name[20], char surname[20]){
CustomerPtr newPtr = (CustomerPtr)malloc(sizeof(Customer));
newPtr->customerId = id;
strcpy(newPtr->customerName, name);
strcpy(newPtr->customerSurname, surname); 
newPtr->next = NULL; /* add this */
CustomerPtr previousPtr, currentPtr;
/* ... */

Answer 2

如果目标是使用链表实现堆栈，那么insert|push需要在列表的开头插入新节点，而不是将其附加到列表的末尾，remove|pop需要删除列表的第一个节点。像这样的插件：

CustomerPtr newPtr = (CustomerPtr)malloc(sizeof(Customer));
newPtr->customerId = id;
strcpy(newPtr->customerName, name);
strcpy(newPtr->customerSurname, surname); 
newPtr->next = *headPtr;
*headPtr = newPtr;