为什么会出现有乱码的呢？而且输出也有问题。。
求高手解答

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct student
{
    char name[20];
    char sno[13];
    int mark;
 }student;

typedef struct Node
{
    student studentInfo;
    struct Node *next;
}LinkList;

LinkList *input()
{
    LinkList *s;
    s=(LinkList *)malloc(sizeof(LinkList));
    s->next=0;
    return s;
}

void insert(LinkList *stu,LinkList *stulist)
{
    LinkList *pointer = stulist;
    LinkList *stupointer =stulist->next;

    while(stupointer!=0&& stupointer->studentInfo.mark<=stu->studentInfo.mark)
    {
        pointer =stupointer;
        stupointer=stupointer->next;
    }
    pointer->next=stu;
    stu->next =stupointer;
}



int search(LinkList *L, char sno[13])
{

    LinkList *S = L,*P;
    while(S && (strcmp(S->studentInfo.sno, sno) != 0))
       S = S->next;
    if(!S->next)
        printf("NO FIND!\n");
    else
    {
        P = S->next;
        S->next = P->next;
        free(S);
    }
    return 0;
}

void main()
{
    LinkList *stulist,*stu,*stupointer;
    stulist=input();
    stu=(LinkList *)malloc(sizeof(LinkList));
    printf("插入3个学生");
    strcpy(stu->studentInfo.sno,"001");
    strcpy(stu->studentInfo.name,"张1");
    stu->studentInfo.mark=90;
    stu->next=0;
    insert(stu,stulist);

    stu=(LinkList *)malloc(sizeof(LinkList));
    strcpy(stu->studentInfo.sno,"002");
    strcpy(stu->studentInfo.name,"张2");
    stu->studentInfo.mark=85;
    stu->next=0;
    insert(stu,stulist);

    stu=(LinkList *)malloc(sizeof(LinkList));
    strcpy(stu->studentInfo.sno,"003");
    strcpy(stu->studentInfo.name,"张3");
    stu->studentInfo.mark=87;
    stu->next=0;
    insert(stu,stulist);
    stupointer=stulist;

    while(stupointer!=0)
    {
        printf("%s,%s,%d\n",stupointer->studentInfo.sno,stupointer->studentInfo.name
                            ,stupointer->studentInfo.mark);

        stupointer=stupointer->next;
    }
    printf("\n");

    printf("删除一个学号为001的学生后：\n");
    search(stu,"001");
    while(stupointer!=0)
    {
        printf("%s,%s,%d\n",stupointer->studentInfo.sno,stupointer->studentInfo.name
                            ,stupointer->studentInfo.mark);

        stupointer=stupointer->next;
    }

}

你在input函数中未对s进行初始化。
input()函数应改为
LinkList *input()
{
    LinkList *s;
    s=(LinkList *)malloc(sizeof(LinkList));
    if(!s)
        exit(OVERFLOW);
    s->studentInfo.name[0]='\0';
    s->studentInfo.sno[0]='\0';
    s->studentInfo.mark=0;
    s->next=NULL;
    return s;
}

另外，你在执行删除操作时，search()函数里面的判断语句
if(!S->next)
        printf("NO FIND!\n");
判断有误。
删除操作执行后，要想输出学生信息，应重新将stupointer指针指向你删除后的链表！

顶  

注意链表的开头和结尾！

似乎不是这里出问题的

    printf("删除学号为002学生后：\n");
    search(stu,"002");
    stupointer = stulist->next;

    while(stupointer!=0)
    {
        printf("%s,%s,%d\n",stupointer->studentInfo.sno,stupointer->studentInfo.name
                            ,stupointer->studentInfo.mark);

        stupointer=stupointer->next;

我加了这句后能显示输出，但他不能按输入的学号删除
//删除功能
int search(LinkList *L, char sno[13])
{

    LinkList *S = L, *P;
    while(S && (strcmp(S->studentInfo.sno, sno) != 0))
       S = S->next;
    if(!S->next)
        printf("NO FIND!\n");  
    else
    {
        P = S->next;
        S->next = P->next;
        free(P);

    }
    return 0;
}

====

[ 本帖最后由 voidx 于 2011-4-18 12:47 编辑 ]

int search(LinkList *L, char sno[13])
{

    //LinkList *S = L,*P;    // S表示要被删除的元素，P表示他的前一个元素，应该像下面那样写：
    LinkList *P = L, *S = P->next;
    while(S && (strcmp(S->studentInfo.sno, sno) != 0)) {
        P = S;    // 记录被删除元素前一个元素的位置
        S = S->next;
    }
    //if(!S->next)    //这个是错的
    if (!S)
        printf("NO FIND!\n");
    else
    {
        //P = S->next;
        //S->next = P->next;
        P->next = S->next;    // 删除元素 S
        free(S);
    }
    return 0;
}

// 在 main() 里：
search(stu,"001");    //楼主太粗心了，居然传递了错误的参数
search(stulist, "001");
// 还有，链表 stulist 的第一个结点是头结点，不保存学生信息，从第二个节点开始才有学生信息，所以
stupointer = stulist;    // 应该改成下面这样
stupointer = stulist->next;    // 注意有两处要修改

另外啊，删除函数还是应该取名 delete。英语不好没关系，咱可以用汉语拼音啊，重要的是表达要清楚

[ 本帖最后由 voidx 于 2011-4-18 13:09 编辑 ]

非常感谢啊·~~不是英文不好，只是因为当时想实现搜索功能，后来放弃了，没改掉而已