已知线性表采用带头结点的单链表存储结构。编写程序：在带头结点的l1中删除在l2中存在的元素，已知线性表采用带头结点的单链表存储结构。编写c语言程序：在带头结点的l1中删除在l2中存在的元素，

这是一个关于编程的问题，我可以回答。下面是一个示例C语言程序：

#include <stdio.h>
#include <stdlib.h>

typedef struct Node {
    int data;
    struct Node *next;
} Node;

void delete_common(Node *l1, Node *l2) {
    Node *p = l1->next;
    Node *pre = l1;
    while (p) {
        Node *q = l2->next;
        int found = 0;
        while (q) {
            if (p->data == q->data) {
                found = 1;
                break;
            }
            q = q->next;
        }
        if (found) {
            pre->next = p->next;
            free(p);
            p = pre->next;
        } else {
            pre = p;
            p = p->next;
        }
    }
}

int main() {
    Node *l1 = (Node *)malloc(sizeof(Node));
    l1->next = NULL;
    Node *l2 = (Node *)malloc(sizeof(Node));
    l2->next = NULL;

    Node *p = l1;
    for (int i = 1; i <= 10; ++i) {
        Node *node = (Node *)malloc(sizeof(Node));
        node->data = i;
        node->next = NULL;
        p->next = node;
        p = p->next;
    }

    p = l2;
    for (int i = 5; i <= 15; ++i) {
        Node *node = (Node *)malloc(sizeof(Node));
        node->data = i;
        node->next = NULL;
        p->next = node;
        p = p->next;
    }

    printf("Before delete_common:\n");
    p = l1->next;
    while (p) {
        printf("%d ", p->data);
        p = p->next;
    }
    printf("\n");

    delete_common(l1, l2);

    printf("After delete_common:\n");
    p = l1->next;
    while (p) {
        printf("%d ", p->data);
        p = p->next;
    }
    printf("\n");

    return 0;
}

这个程序实现了在带头结点的l1中删除在l2中存在的元素的功能。具体来说，它遍历l1中的每个元素，然后在l2中查找是否存在相同的元素。如果存在，则在l1中删除该元素。最后，程序输出删除前和删除后的l1中的元素，以验证程序的正确性。