某一元多项式采用带头节点的单链表存储，编写c语言算法求其导数

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

typedef struct node {
    int coef;  // 系数
    int exp;   // 指数
    struct node *next;
} PolyNode, *PolyList;

// 创建多项式
void createPoly(PolyList *L)
{
    int coef, exp, flag;
    PolyNode *p, *tail;
    *L = (PolyNode *)malloc(sizeof(PolyNode));  // 创建头节点
    (*L)->next = NULL;
    tail = *L;
    printf("请输入多项式的系数和指数（系数为0时停止输入）：\n");
    do {
        flag = scanf("%d %d", &coef, &exp);
        if (flag && coef != 0) {
            p = (PolyNode *)malloc(sizeof(PolyNode));
            p->coef = coef;
            p->exp = exp;
            tail->next = p;
            tail = p;
        }
    } while (flag && coef != 0);
    tail->next = NULL;
}

// 输出多项式
void printPoly(PolyList L)
{
    PolyNode *p = L->next;
    while (p) {
        if (p->coef > 0 && p != L->next) printf("+");
        if (p->coef != 1 || p->exp == 0) printf("%d", p->coef);
        if (p->exp > 0) printf("x");
        if (p->exp > 1) printf("^%d", p->exp);
        p = p->next;
    }
    printf("\n");
}

// 求导数
void derivative(PolyList L)
{
    PolyNode *p = L->next, *pre = L;
    while (p) {
        if (p->exp == 0) {  // 如果指数为0，将该节点删除
            pre->next = p->next;
            free(p);
            p = pre->next;
        } else {
            p->coef *= p->exp;  // 求导数
            p->exp--;
            pre = p;
            p = p->next;
        }
    }
}

int main()
{
    PolyList L;
    createPoly(&L);
    printf("多项式：");
    printPoly(L);
    derivative(L);
    printf("导数：");
    printPoly(L);
    return 0;
}