我在C中使用链表的插入方法遇到一些麻烦。它似乎仅添加在表的开头。我进行的任何其他插入操作都会失败。而且这个CodeBlocks调试器很难理解,我仍然不明白。它从不给我值(value),只是给内存中的地址。无论如何,这是我的职责。您是否看到失败的任何原因?
/* function to add a new node at the end of the list */
int addNodeBottom(int val, node *head){
//create new node
node *newNode = (node*)malloc(sizeof(node));
if(newNode == NULL){
fprintf(stderr, "Unable to allocate memory for new node\n");
exit(-1);
}
newNode->value = val;
//check for first insertion
if(head->next == NULL){
head->next = newNode;
printf("added at beginning\n");
}
else
{
//else loop through the list and find the last
//node, insert next to it
node *current = head;
while(current->next != NULL)
{
if(current->next == NULL)
{
current->next = newNode;
printf("added later\n");
}
current = current->next;
}
}
return 0;
}
然后,主要是仅添加929。
//testing addNodeBottom function
addNodeBottom(929, head);
addNodeBottom(98, head);
addNodeBottom(122, head);
addNodeBottom(11, head);
addNodeBottom(1034, head);
最佳答案
此代码将起作用。 samplebias的答案几乎是正确的,但是您需要进行第三次更改:
int addNodeBottom(int val, node *head){
//create new node
node *newNode = (node*)malloc(sizeof(node));
if(newNode == NULL){
fprintf(stderr, "Unable to allocate memory for new node\n");
exit(-1);
}
newNode->value = val;
newNode->next = NULL; // Change 1
//check for first insertion
if(head->next == NULL){
head->next = newNode;
printf("added at beginning\n");
}
else
{
//else loop through the list and find the last
//node, insert next to it
node *current = head;
while (true) { // Change 2
if(current->next == NULL)
{
current->next = newNode;
printf("added later\n");
break; // Change 3
}
current = current->next;
};
}
return 0;
}
更改1:必须将
newNode->next
设置为NULL
,这样我们才不会在列表末尾插入无效的指针。更改2/3:将循环更改为无穷循环,当我们找到最后一个元素时,该循环将使用
break;
跳出。请注意while(current->next != NULL)
与以前的if(current->next == NULL)
相矛盾。编辑:关于while循环,这种方式要好得多:
node *current = head;
while (current->next != NULL) {
current = current->next;
}
current->next = newNode;
printf("added later\n");
关于最后是C链表插入节点,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/5797548/