C 中链表的插入排序？

我尝试寻找与我类似的问题，但没有找到太多帮助。

我有一个此类结构的链接列表：

struct PCB {
    struct PCB *next;
    int reg1, reg2;
};

我首先创建 10 个 PCB 结构，以这种方式链接在一起：

for(i=20;i<=30;i++) {
        curr = (struct PCB *)malloc(sizeof(struct PCB));
        curr->reg1 = i;
        curr->next  = head;
        head = curr;
    }

然后我需要创建另外 20 个 PCB 结构，但是它们reg1值需要使用生成rand()。我目前正在这样做：

for (j = 0;j<20;j++) {
        curr = (struct PCB *)malloc(sizeof(struct PCB));
        curr->reg1 = rand()%100;
        curr->next  = head;
        head = curr;
    }

然而，当将这些 PCB 结构体随机插入到链表中时reg1值，我需要将它们按顺序插入到链接列表中（插入排序）。在单链接链表中解决这个问题的最佳方法是什么？谢谢

编辑： 我现在正在跟踪第一个创建的结构，以便能够从头开始循环遍历链表：

// create root struct to keep track of beginning of linked list
root = (struct PCB *)malloc(sizeof(struct PCB));
root->next = 0;  
root->reg1 = 20;

head = NULL;

// create first 10 structs with reg1 ranging from 20 to 30
for(i=21;i<=30;i++) {
    curr = (struct PCB *)malloc(sizeof(struct PCB));
    // link root to current struct if not yet linked
    if(root->next == 0){
        root->next = curr;
    }
    curr->reg1 = i;
    curr->next  = head;
    head = curr;
}

然后，当我创建另外 10 个需要插入排序的 PCB 结构时：

// create 20 more structs with random number as reg1 value
    for (j = 0;j<20;j++) {
        curr = (struct PCB *)malloc(sizeof(struct PCB));
        curr->reg1 = rand()%100;
        // get root for looping through whole linked list
        curr_two = root;
        while(curr_two) {
            original_next = curr_two->next;
            // check values against curr->reg1 to know where to insert
            if(curr_two->next->reg1 >= curr->reg1) {
                // make curr's 'next' value curr_two's original 'next' value
                curr->next = curr_two->next;
                // change current item's 'next' value to curr
                curr_two->next = curr;
            }
            else if(!curr_two->next) {
                curr->next = NULL;
                curr_two->next = curr;
            }
            // move to next struct in linked list
            curr_two = original_next;
        }
        head = curr;
    }

但这立即使我的程序崩溃了。

“最好”的方法可能是实现一个新的插入功能。该函数将迭代列表，直到找到一个节点，该节点的next节点值小于或等于要插入的节点，则将新节点放在next node.

这个功能怎么样：

void insert(struct PCB **head, const int reg1, const int reg2)
{
    struct PCB *node = malloc(sizeof(struct PCB));
    node->reg1 = reg1;
    node->reg2 = reg2;
    node->next = NULL;

    if (*head == NULL)
    {
        /* Special case, list is empty */
        *head = node;
    }
    else if (reg1 < (*head)->reg1)
    {
        /* Special case, new node is less than the current head */
        node->next = *head;
        *head = node;
    }
    else
    {
        struct PCB *current = *head;

        /* Find the insertion point */
        while (current->next != NULL && reg1 < current->next->reg1)
            current = current->next;

        /* Insert after `current` */
        node->next = current->next;
        current->next = node;
    }
}

你可以这样称呼它：

insert(&root, rand() % 100, 0);