要求写一个程序，读入学生姓名，学好。英语数学语文成绩。。将其放在文件里，在查询期中的学生信息，我想达到的目标是一输入学生学号，就能得到该学生的这些信息。。。。

#include<stdio.h>
FILE *fp;

struct
{
    int num;
    char name[20];
    double score[4];

}stu[20];
void input(void);
void search(void);


int main(void)
{
    int n;
    printf("您已经进入了学生查询系统\n");
    printf("1学生信息录入\n");
    printf("2学生信息查询\n");
    do
    {
        scanf(" %d", &n);
        switch(n)
        {
            case 1:
            input();
            break;
            case 2:
            search();
            break;
        }
        if(n>2)
        {
            printf("您输入的选项有误！\n");
        }

    }while(n!=0);

    return 0;
}
void input(void)
{
    int i = 0;
    if((fp=fopen("filename", "w")) == NULL){
    printf ("打开文件失败！\n");
    exit(0);
    }
    do
    {
        printf("请输入学生学号 姓名 语文 数学 英语；\n");
        fscanf ("%f%s%f%f%f",&stu[i].num,stu[i].name,&stu[i].score[0],&stu[i].score[1],&stu[i].score[2],&stu[i].score[3]);
        stu[i].score[3] = stu[i].score[1] + stu[i].score[2] +stu[i].score[3]/3;



    }while(stu[i].num !=0);
    fclose(fp);
}
void search(void)
{
    int num, k=0, i=0;
    if((fp=fopen("filename","r"))==NULL)
    {
    printf("不能打开");
    exit(0);
    }
    printf("请输入你要查询学生信息");
    do
    {
        while(!feof(fp)){
        scanf("%d",&num);
        fscanf (fp,"%f%s%f%f%f",&stu[i].num,stu[i].name,&stu[i].score[0],&stu[i].score[1],&stu[i].score[2],&stu[i].score[3]);
        if(num == stu[i].num)
        {
            fprintf ("%d %s %.1f  %.1f %.1f %.1f",&stu[i].num,stu[i].name,&stu[i].score[0],&stu[i].score[1],&stu[i].score[2],&stu[i].score[3]);

        k=1;
        break;
        }
        }
        if(k=0)
        printf ("没有该学生的信息！\n");
        printf("请重新输入:\n");

     }while(num!=0);
     fclose(fp);

#include "stdio.h"
#include"stdlib.h"
#include"string.h"


typedef struct student//定义学生
{
    char name[10];
    int number;
    char sex[2];
    int math;
    int eglish;
    int clanguge;
    int total;
    float average;
}student;

typedef struct unit//定义接点
{
    student date;
    struct unit *next;
}unit;


unit* build()//建立链表并返回指针
{
    unit *p;
    if((p=(unit*)malloc(sizeof(unit)))==NULL)
     { printf("=>初始化失败！");
         return 0;
     }
    else
     {p->next=NULL;
         p->date.number=0;//头结点存放学生人数
      printf("初始化成功！\n");
      return p;
     }
}


void add(unit *head)//增加学生
{
    unit *p,*q;
    int m,n=0;
    q=head->next;
    p=(unit*)malloc(sizeof(unit));
    printf("=>请输入新生姓名！\n");
    gets(p->date.name);fflush(stdin);
    printf("=>请输入学号！\n");
    while(n==0)
    {
        scanf("%d",&m);fflush(stdin);
        if(q==NULL) n=1;
        while(q)
        {
            if(q->date.number==m)
            {
               printf("=>你输入的学号与已有同学的学号相同,请重新输入！\n");
               q=head->next;
               break;
            }
        
            else
            {
               q=q->next;
               if(q==NULL) n=1;
            }
        }
    }
    p->date.number=m;
    printf("=>请输入性别！\n");
    gets(p->date.sex);fflush(stdin);
    printf("=>请输入数学成绩\n");
    scanf("%d",&m);fflush(stdin);
    p->date.math=m;
    printf("=>请输入英语成绩\n");
    scanf("%d",&m);fflush(stdin);
    p->date.eglish=m;
    printf("=>请输入c语言成绩\n");
    scanf("%d",&m);fflush(stdin);
    p->date.clanguge=m;
    p->date.total=(p->date.math+p->date.eglish+p->date.clanguge);
    p->date.average=p->date.total/3.0;
    q=head->next;
    head->next=p;
    p->next=q;
    head->date.number++;
}
   

void deletion(unit *head)//删除一名学生
{
    unit *p=head->next,*q=head;
    char N[10];
    printf("请输入你想删除的学生姓名！\n");
    gets(N);fflush(stdin);
    if(p==NULL)
    printf("系统无学生可删除！\n");
    while(p)
    {
        if(strcmp(p->date.name,N)==0)
        {
            q->next=p->next;
            head->date.number--;
            printf("删除%s成功！\n",p->date.name);
            free(p);
            break;
        }
        else
        {
            p=p->next;
            q=q->next;
            if(p==NULL)
            printf("你要删除的学生不存在,删除失败！\n");
        }
    }

}


int display(unit *head)//显示学生信息
{
    unit *p=head->next;
    int m,n=0;
    char N[10];
    if(p==NULL)
    {
        printf("系统无学生信息！\n");
        return 0;
    }
    while(n==0)
    {
        printf("******************************************************************************\n");
        printf("请选择你的操作！\n");
        printf("\t\t\t1.显示所有\t2.按姓名查找\n\t\t\t3.按学号查找\t4.返回主菜单\n");
        scanf("%d",&m);
        fflush(stdin);
        switch(m)
        {
            case 1:printf("\n该系统拥有%d名学生！\n\n",head->date.number);
                   p=head->next;
                   printf("\t 姓名      学号        性别    数学     英语   c语言    综合      平均分\n\n");
                   while(p)
                    {
                        printf("\t%s\t%d\t%s\t%d\t%d\t%d\t%d\t%8.2f\n",p->date.name,p->date.number,p->date.sex,p->date.math,
                        p->date.eglish,p->date.clanguge,p->date.total,p->date.average);
                        p=p->next;
                    }
                    break;
            case 2:printf("请输入查找姓名！\n");
                   gets(N);
                   fflush(stdin);
                   p=head->next;
                  while(p)
                   {
                       if(strcmp(p->date.name,N)==0)
                    {
                         printf("\t 姓名      学号        性别    数学     英语   c语言    综合      平均分\n\n");
                        printf("\t%s\t%d\t%s\t%d\t%d\t%d\t%d\t%8.2f\n",p->date.name,p->date.number,p->date.sex,p->date.math,
                        p->date.eglish,p->date.clanguge,p->date.total,p->date.average);
                        break;
                    }
                    else
                    {
                        p=p->next;
                        if(p==NULL)
                        printf("你要查的学生不存在！");
                    }
                   }
                    break;
              case 3: printf("请输入查找学号！\n");
                   scanf("%d",&m);
                   fflush(stdin);
                  p=head->next;
                  while(p)
                   {
                       if(p->date.number==m)
                    {
                         printf("\t 姓名      学号        性别    数学     英语   c语言    综合      平均分\n\n");
                        printf("\t%s\t%d\t%s\t%d\t%d\t%d\t%d\t%8.2f\n",p->date.name,p->date.number,p->date.sex,p->date.math,
                        p->date.eglish,p->date.clanguge,p->date.total,p->date.average);
                        break;
                    }
                    else
                    {
                        p=p->next;
                        if(p==NULL)
                        printf("你要查的学生不存在！\n");
                    }
                   }
                    break;
             case 4:n=1;break;
        }
    }
    return 1;
}
                              



int range(unit *head)//排序
{
    unit *p=head,*q=head->next;
    int n,i,m=head->date.number;
    printf("*******************************************************************************\n");
    printf("\t\t\t1.按学号\t2.按成绩\n\n");
    printf("请选择操作！\n》");
    scanf("%d",&n);
    fflush(stdin);
    if(q==NULL)
    { printf("无学生可排序！\n");
        return 0;
    }
    switch(n)
    {
        case 2:for(i=0;i<m;i++)//按总分排序
                {
                    p=head;q=head->next;
                    while(q->next)
                    {
                        if((q->date.average)<(q->next->date.total))
                        {
                            p->next=q->next;
                            p=p->next;
                            q->next=p->next;
                            p->next=q;
                        }
                        else
                        {
                            p=p->next;q=q->next;
                        }
                    }
                }
                break;

         case 1:for(i=0;i<=m;i++)//按学号排序
                {
                    p=head;q=head->next;
                    while(q->next)
                    {
                        if((q->date.number)>(q->next->date.number))
                        {
                            p->next=q->next;
                            p=p->next;
                            q->next=p->next;
                            p->next=q;
                        }
                        else
                        {
                            p=p->next;q=q->next;
                        }
                    }
                }
                break;
    }
    printf("排序成功！\n");
    return 1;
}




void menu()
{
    printf("\n********************************* 主菜单 ***************************************\n");
   
    printf("\t\t\t1.添加学生\t2.删除学生\n\t\t\t3.查看信息\t4.排列顺序\n\t\t\t5.保存信息\t6.退出系统\n\n");
    printf("请选择你的操作！\n");
}


int save(unit *head)//保存
{
    FILE *fp;
    unit *p;
    p=head;
    if((fp=fopen("d:\\学生","wb+"))==NULL)
    {
        printf("保存失败！");
        return 0;
    }
   while(p)
    {fwrite(&(p->date),sizeof(student),1,fp);
    p=p->next;
    }
    printf("保存成功！");
   fclose(fp);
   return 1;
}



unit* read()//读入系统学生信息
{
    int i;
    unit *p,*q,*head;
    FILE *fp;
    if((head=(unit*)malloc(sizeof(unit)))==NULL)
     { printf("开辟空间失败！");
         exit(1);
     }
    else
     {
         head->next=NULL;
         head->date.number=0;//头结点存放学生人数
     }
    q=head;
 if((fp=fopen("d:\\学生","rb"))==NULL)
   {printf("系统暂无学生信息！\n");
    return 0;
    }
 fread(&(q->date),sizeof(student),1,fp);
 for(i=0;i<head->date.number;i++)
 {
     if((p=(unit*)malloc(sizeof(unit)))==NULL)
     { printf("读值失败！");
         exit(1);
     }
    fread(&(p->date),sizeof(student),1,fp);
    p->next=q->next;
    q->next=p;
 }
 fclose(fp);
 return head;
}

void main()
{
    int m=0,n, i;
     unit *head;
     printf("\n\n\n\n");
     printf("\t\t\t* 欢迎使用学生成绩管理系统 * \n");
     if((head=read())==0)
     {
         printf("该系统暂无学生信息!--是否新建？(---是(1).否(2).)\n");
           scanf("%d",&i);
           fflush(stdin);
           if(i==1)
             head=build();
           else if(i==2)
             exit(1);
     }
     else
     printf("信息导入成功！");
    while(m==0)
    {
        menu();
        scanf("%d",&n);
        fflush(stdin);
     switch(n)
     {
      
         case 1:add(head);break;
         case 2:deletion(head);break;
         case 3:display(head);break;
         case 4:range(head);break;
         case 5:save(head);break;
         case 6:m=1;break;
     }
   }
}
这个是我以前做的  你可以参考一下 看哪块能用得上

楼上这代码真是多得可怕啊...

帮帮改改啊，哥们。。我现在也没学指针。。我们现在C语言就指针没有讲了。。。我想有人帮我在原来基础上帮帮如何变下。。。。。谢谢啊！

等大神吧，  我也想学学