代码可以运行，但是调试出现弹窗错误（软件devc++）

本题要求实现两个函数，一个将输入的学生成绩组织成单向链表；另一个将成绩低于某分数线的学生结点从链表中删除。

函数接口定义：
struct stud_node *createlist();
struct stud_node *deletelist( struct stud_node *head, int min_score );
函数createlist利用scanf从输入中获取学生的信息，将其组织成单向链表，并返回链表头指针。链表节点结构定义如下：

struct stud_node {
int num; /学号/
char name[20]; /姓名/
int score; /成绩/
struct stud_node *next; /指向下个结点的指针/
};
输入为若干个学生的信息（学号、姓名、成绩），当输入学号为0时结束。

函数deletelist从以head为头指针的链表中删除成绩低于min_score的学生，并返回结果链表的头指针。

裁判测试程序样例：

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

struct stud_node {
     int    num;
     char   name[20];
     int    score;
     struct stud_node *next;
};

struct stud_node *createlist();
struct stud_node *deletelist( struct stud_node *head, int min_score );

int main()
{
    int min_score;
    struct stud_node *p, *head = NULL;

    head = createlist();
    scanf("%d", &min_score);
    head = deletelist(head, min_score);
    for ( p = head; p != NULL; p = p->next )
        printf("%d %s %d\n", p->num, p->name, p->score);

    return 0;
}

/* 你的代码将被嵌在这里 */

下面是我的代码

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

struct stud_node {
     int    num;
     char   name[20];
     int    score;
     struct stud_node *next;
};

struct stud_node *createlist();
struct stud_node *deletelist( struct stud_node *head, int min_score );

int main()
{
    int min_score;
    struct stud_node *p, *head = NULL;

    head = createlist();
    scanf("%d", &min_score);
    head = deletelist(head, min_score);
    for ( p = head; p != NULL; p = p->next )
        printf("%d %s %d\n", p->num, p->name, p->score);

    return 0;
}
struct stud_node *createlist(){
 struct stud_node* head;
 head=(struct stud_node *)malloc(sizeof(struct stud_node));
 head->num=-1;
 strcpy(head->name," ");
 head->score=-1;
 head->next=NULL;
 struct stud_node* p=head;
 while(1){
  struct stud_node* new_node=(struct stud_node*)malloc(sizeof(struct stud_node));
  scanf("%d",&(new_node->num));
  if(new_node->num==0){
   new_node->next=NULL;
   break;
  }
  scanf("%s%d",new_node->name,&(new_node->score));
  p->next=new_node;
  p=new_node;
 }
 head=head->next;
 return head;
}
struct stud_node *deletelist( struct stud_node *head, int min_score ){
 struct stud_node *p,*q;
 p=head;
 q=NULL;
 while(p!=NULL){
  if(p->score<min_score&&q==NULL){
   head=p->next;
   free(p);
   p=head;
   q=NULL;
  }
  else{
   break;
  }
 }
 q=head;
 p=head->next; 
 while(p!=NULL){
  if(p->score<min_score){
   q->next=p->next;
   free(p);
   p=q;
   p=p->next;
  } 
  else{
   q=p;
   p=p->next;
  }
  
 }
 return head;
}

我在C:B里编译没有任何问题，程序也可以执行。如果能把错误提示窗口截图或许可以更好的帮助到你。

修改见注释，供参考：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>  
struct stud_node {
    int    num;
    char   name[20];
    int    score;
    struct stud_node* next;
};
struct stud_node* createlist();
struct stud_node* deletelist(struct stud_node* head, int min_score);
int main()
{
    int min_score;
    struct stud_node* p, * head = NULL;
    head = createlist();
    scanf("%d", &min_score);
    head = deletelist(head, min_score);
    for (p = head; p != NULL; p = p->next)
        printf("%d %s %d\n", p->num, p->name, p->score);
    return 0;
}
struct stud_node* createlist() {
    struct stud_node* head = NULL, * p;
    //head = (struct stud_node*)malloc(sizeof(struct stud_node)); //修改
    //head->num = -1;
    //strcpy(head->name, " ");
    //head->score = -1;
    //head->next = NULL;
    //struct stud_node* p = head;
    while (1) {
        struct stud_node* new_node = (struct stud_node*)malloc(sizeof(struct stud_node));
        new_node->next = NULL;                //修改
        scanf("%d", &(new_node->num));
        if (new_node->num == 0) {
            //new_node->next = NULL;          //修改
            free(new_node);                  //修改
            break;
        }
        scanf("%s%d", new_node->name, &(new_node->score));
        if (head == NULL) {                  //修改
            head = new_node;                 //修改
            p = new_node;                    //修改
        }
        else{
            p->next = new_node;             
            p = new_node;
        }
    }
    //head = head->next;                     //修改
    return head;
}
struct stud_node* deletelist(struct stud_node* head, int min_score) 
{
    struct stud_node* p, * q;
    p = head;
    q = NULL;
    while (p != NULL) {
        if (p->score < min_score) 
        {
            if (q == NULL) {                //修改
                head = p->next;
                free(p);
                p = head;
                q = NULL;
            }
            else {                          //修改
                q->next = p->next;
                free(p);
                p = q;
                p = p->next;
            }
        }
        else {
            //break;                      //修改
            q = p;
            p = p->next;
        }
    }
    //q = head;
    //p = head->next;
    //while (p != NULL) {
    //    if (p->score < min_score) {
    //        q->next = p->next;
    //        free(p);
    //        p = q;
    //        p = p->next;
    //    }
    //    else {
    //        q = p;
    //        p = p->next;
    //    }
    //}
    return head;
}