struct chexinxi *duqu() { struct chexinxi *head2= NULL; struct chexinxi *temp = NULL; char chexinghao[20], chepaihao[20]; FILE *fp = fopen("车辆信息.txt", "r"); if (fp == NULL) { printf("\t\t\t\t打开文件失败！文件名：%s，错误码：%d\n", "车辆信息.txt", errno); } else { while (fscanf(fp, "%s %s", chexinghao, chepaihao) != EOF) { struct chexinxi *p = malloc(sizeof(struct chexinxi)); if (p == NULL) { printf("分配内存失败！\n"); } strcpy(p->chexinghao, chexinghao); strcpy(p->chepaihao, chepaihao); if (head2 == NULL) { head2 = temp = p; } else { temp->next = p; temp = p; } } fclose(fp); if (temp != NULL) { temp->next = NULL; } return head2; } return; }是否有错

这段代码在处理文件打开失败的情况时进行了错误处理，但是在文件打开成功时缺少了返回指针的语句，导致程序会进入到无返回值的分支并且出现编译错误。因此，需要在文件处理完成后添加返回指针的语句，如下所示：

struct chexinxi *duqu()  {     
    struct chexinxi *head2= NULL;     
    struct chexinxi *temp = NULL;     
    char chexinghao[20], chepaihao[20];     
    FILE *fp = fopen("车辆信息.txt", "r");     
    if (fp == NULL) {         
        printf("\t\t\t\t打开文件失败！文件名：%s，错误码：%d\n", "车辆信息.txt", errno); 
        return NULL; // 文件打开失败，返回空指针
    } else {         
        while (fscanf(fp, "%s %s", chexinghao, chepaihao) != EOF) {             
            struct chexinxi *p = malloc(sizeof(struct chexinxi));             
            if (p == NULL) {                 
                printf("分配内存失败！\n");             
            }             
            strcpy(p->chexinghao, chexinghao);             
            strcpy(p->chepaihao, chepaihao);             
            if (head2 == NULL) {                 
                head2 = temp = p;             
            } else {                 
                temp->next = p;                 
                temp = p;             
            }         
        }         
        fclose(fp);         
        if (temp != NULL) {             
            temp->next = NULL;         
        }         
        return head2; // 文件处理完成，返回链表头指针
    }     
}