#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*Creat_Stu_Doc();
void Print_Stu_Doc(struct stud_node*head);
struct stud_node*Creat_Stu_Doc()
{
    struct stud_node*head,*p;
    int num,score;
    char name[20];
    int size = sizeof(struct stud_node);
    head = NULL;
    printf("input num,name and score:\n");
    scanf("%d%s%d",&num,name,&score);
    while(num!=0){
        p=(struct stud_node*)malloc(size);
        p->num=num;
        strcpy(p->name,name);
        p->score= score;
        
    }
    return head;
}
void Print_Stu_Doc(struct stud_node*head)
{
    struct stud_node*ptr;
    if(head == NULL){
        printf("\nNo Records\n");
        return ;
    }
    printf("\nthe students`records are:\n");
    printf("   num   name   score\n");
    for(ptr=head;ptr;ptr=ptr->next)
    printf("%8d%20s%6d\n",ptr->num,ptr->name,ptr->score);
   
}
int main(void)
{
    struct stud_node*head,*p;
    int choice,num,score;
    char name[20];
    int size = sizeof(struct stud_node);
   
    do{
        printf("1:create 2:print 0:exit\n");
        scanf("%d",&choice);
        switch(choice){
            case 1:
            head=Creat_Stu_Doc();
            break;
            case 2:
            Print_Stu_Doc(head);
            break;
            case 0:
            break;
        }
        
    }while(choice != 0);
        return 0;
}
运行貌似有问题 帮忙看下

没人顶？

改完后代码如下：
#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*Creat_Stu_Doc();
void Print_Stu_Doc(struct stud_node*head);
struct stud_node*Creat_Stu_Doc()
{
    struct stud_node*head,*p;
    int num,score;
    char name[20];
    int size = sizeof(struct stud_node);
    head = NULL;
    printf("input num,name and score:\n");
    scanf("%d%s%d",&num,name,&score);
    while(num!=0){
        p=(struct stud_node*)malloc(size);
        p->num=num;
        strcpy(p->name,name);
        p->score= score;
        p->next = NULL; //封口
        break; //这里停不下来了加个BREAK吧。
    }
    return p; //你处理的是P返回没处理的HEAD当然不行了。。
}
void Print_Stu_Doc(struct stud_node*head)
{
    struct stud_node*ptr;
    if(head == NULL){
        printf("\nNo Records\n");
        return ;
    }//下面这里又无限了，改一下，先处理再判断，没有时上面已经判断了
    printf("\nthe students`records are:\n");
    printf("   num   name   score\n");
    ptr=head;
    printf("%8d%20s%6d\n",ptr->num,ptr->name,ptr->score); //这里没对齐不知道什么意思，我就不改了
    while (ptr->next != NULL){
    ptr = ptr->next;
    printf("%8d%20s%6d\n",ptr->num,ptr->name,ptr->score); //
    }

   
}
int main(void)
{
    struct stud_node*head,*p;
    //int choice,num,score; //没用上，注释掉
    int choice;
    //char name[20]; //也是没用上
    int size = sizeof(struct stud_node);
   

    head = (struct stud_node*)malloc(size);//先申一个吧。
    head->next = NULL; //封口
    p = head; //临时指向
    do{
        printf("1:create 2:print 0:exit\n");
        scanf("%d",&choice);

        switch(choice){
            case 1:
            p->next=Creat_Stu_Doc();
            p=p->next; //想要链表就得考虑下一个。
            break;
            case 2:
            Print_Stu_Doc(head->next); //遍历从第2个开始
            break;
            case 0:
            break;
        }
        
    }while(choice != 0);
        return 0;
}

测试：
1:create 2:print 0:exit
2

No Records
1:create 2:print 0:exit
1
input num,name and score:
1 li 100
1:create 2:print 0:exit
2

the students`records are:
   num   name   score
       1                  li   100
1:create 2:print 0:exit
1
input num,name and score:
2 wang 200
1:create 2:print 0:exit
2

the students`records are:
   num   name   score
       1                  li   100
       2                wang   200
1:create 2:print 0:exit
0
请按任意键继续. . .
VC6，CFREE4.1通过。。