c语言链表问题

初步改了下。。。能力有限。。。
#include"stdio.h"
#include"stdlib.h"
#define LEN sizeof(struct Student)
typedef struct Student {
    long num;
    char name[20];
    char sex[5];
    int old;
    struct Student *next;
}Student;
int n=0;
/*建立链表（不止一种方式）*/
Student *creat(void){
    Student *head,*p;long num;
    p=head=(Student *)malloc(LEN);  
    while(1){
        p->next=(Student *)malloc(LEN);
        printf("输入第%d学生的信息（学号(学号为零就结束):",n+1);scanf("%ld",&num);
        if(num==0)break;p->num=num;
        printf("输入第%d学生的姓名:",n+1);scanf("%s",p->name);
        printf("输入第%d学生的性别（man or woman）:",n+1);scanf("%s",p->sex);
        printf("输入第%d学生的年龄:",n+1);scanf("%d",&p->old);
        n++;
        p=p->next;
    }
    p=NULL;
    return head;
}
Student *del(Student *head,int old){
    Student *p=head,*q;int c=0;
    while(c<n){
        if(p->next->old==old){
            q=p->next;
            p->next=q->next;
        }
        p=p->next;c++;
    }  
    n--;
    return (head);
}
void print(Student *head){
    Student *p=head;int cc=0;
    printf("\nnow these %d records are:\n",n);
    while(cc<n){
        printf("%ld,%s,%s,%d\n",p->num,p->name,p->sex,p->old);
        p=p->next;cc++;
    }
}
int main(void){
    int old;
    Student *head;
    head=creat();
    printf("输入一个年龄：");
    scanf("%d",&old);
    head=del(head,old);
    print(head);
    return 0;
}

没仔细看，不过受源码框架的限制，建议做大的调整。

不是说非要什么固定的模板，只是说基础的链表处理要恰当，其次才是添加一些个性化的东西
如你做的结点内容的扩充，先解决的就是链表的增删改查其次才是枝枝叶叶的东西。
我做的可能有Bug的话，还是用LinkedList，HashMap试试，而且算法封装了处理简单。
要自己思考。。。。。。
#include<stdio.h>
#include<stdlib.h>
typedef struct Student{
     long num;
     char name[20];
     char sex[5];
     int old;
     struct Student *next;
}Studet;                  

Student *build(int k){
    int i;
    Student *head=(Student *)malloc(sizeof(Student));      
    Student *p=head;
    for(i=1;i<k;i++){
        printf("input the NO.%d element:",i);      
        p->next=(Student *)malloc(sizeof(Student));
        printf("输入第%d学生的信息\n学号:",i);scanf("%ld",&p->num);
        printf("输入第%d学生的姓名:",i);scanf("%s",p->name);
        printf("输入第%d学生的性别（man or woman）:",i);scanf("%s",p->sex);
        printf("输入第%d学生的年龄:",i);scanf("%d",&p->old);  
        p=p->next;
    }               
    printf("输入第%d学生的信息\n学号:",i);scanf("%ld",&p->num);
    printf("输入第%d学生的姓名:",i);scanf("%s",p->name);
    printf("输入第%d学生的性别（man or woman）:",i);scanf("%s",p->sex);
    printf("输入第%d学生的年龄:",i);scanf("%d",&p->old);            
    p->next=NULL;
    return head;
}      

void display(Student *h){
     Student *p=h;int c=0;
     while(p){
         p=p->next;c++;
     }p=h;
     printf("\nnow these %d records are:\n",c);
     while(p->next!=NULL){
        printf("%ld,%s,%s,%d\n",p->num,p->name,p->sex,p->old);
        p=p->next;
    }
    printf("%ld,%s,%s,%d\n",p->num,p->name,p->sex,p->old);   
}   

Student *del(Student *h,int old){
    Student *p=h,*q=h;
    if(p->old==old)h=h->next;
    else
    while(p->next){
        q=p->next;
        if(q->old==old&&q){
            if(q->next==NULL){p->next=NULL;break;}
            else p->next=q->next;
        }
        p=p->next;
    }   
    return h;
}
main(){
    Studet *head;
    int k,old;
    printf("input the length of Line:");
    scanf("%d",&k);
    head=build(k);
    display(head);
    printf("输入一个年龄：");
    scanf("%d",&old);
    head=del(head,old);
    display(head);
}