最近在做C语言的课程设计
今天搞好了 放上来给大家看看，欢迎拍砖
/*
基本思路：
读

用fread读出一个学生信息写到输入缓存（struct student a）中 判断缓存中的值是否符合

写

输入一个学生信息到输出缓存（struct student b）中，再用fwrite写到文件中；
*/















#include<stdio.h>
#include<string.h>
#include<stdlib.h>
struct stud
{
   long int num;
   char name[10];
   float C_Score;
   float M_Score;
   float E_Score;
};

int xiugai()   //修改学生信息
{
   FILE *fp;
   struct stud *p;
   struct stud a,b;
   long int num;
   p=&b;
  
  printf("\nplease input num\n ");

  scanf("%ld",&num);
  
  printf("\nplease input num,name,C_Score,M_Score,E_score\n");

  scanf("%ld%s%f%f%f",&XXXXm,XXXXme,&a.C_Score,&a.M_Score,&a.E_Score);

  

fp=fopen("student","rb+");



  while(1)
  {
      
      fread(&b,sizeof(b),1,fp);
    
      if(p->num==num) break;
      else if(p->num==0) {break; printf("error");}
      
  
  
  }


   fseek(fp,-sizeof(a),1);        //文件指针定位
   fwrite(&a,sizeof(a),1,fp);

   fclose(fp);
  
   printf(".....done\n");

    

    return(0);

  
      printf("......done");
}

int tongji()   //成绩统计
{
   int x; int sum=0 ,all=0;float AVR;
  
   float score1,score2;
  
   struct stud a; struct stud *p; float *q;
   FILE *fp;

   p=&a;
  
   printf("\nplease input xueke(1.m or 2.c or 3.e)\n");
   scanf("%d",&x);
   printf("\nplease input score duan(score1,score2)\n");
   scanf("%f,%f",&score1,&score2);
   if((score1==0)||(score1>score2)) {printf("error"); return(0);}

   switch(x)
   {
      case 1 :q=&p->M_Score;break;
      case 2 :q=&p->C_Score;break;
      case 3 :q=&p->E_Score;break;
   }


   fp=fopen("student","rb");
   while(1)
  {
     fread(&a,sizeof(a),1,fp);
     while((*q>score1)&&(*q<score2))
     {
        printf("%ld,%s,%5.1f,%5.1f,%5.1f\n",XXXXm,XXXXme,a.C_Score,a.M_Score,a.E_Score);
        sum++;
        all=all+p->C_Score+p->M_Score+p->E_Score;
        
        break;
        
     }
    
     if((p->num==0)&&(sum==0))
     {
         printf("error\n");
         break;
     }
     if(p->num==0) break;
  }

  AVR=all/sum;
  printf("sum is %d\nall is %d\n AVR is %5.3f\n",sum,all,AVR);
       printf("......done");
  return(0);
  
}

int namechaxun()   //姓名查询
{
   char name[10];
   struct stud a; struct stud *p;
   FILE *fp;

   p=&a;
  
   printf("\nplease input name\n");
   scanf("%s",name);

   fp=fopen("student","rb");
   while(1)
  {
     fread(&a,sizeof(a),1,fp);
     if(strcmp(XXXXme,name) == 0)
     {
        printf("%ld,%s,%5.1f,%5.1f,%5.1f\n",XXXXm,XXXXme,a.C_Score,a.M_Score,a.E_Score);
        break;
     }
     else if(p->num==0)
     {
         printf("name error\n");
         break;
     }
  }
       printf("......done");
  return(0);
  
}

int xuehaochaxun()  //学号查询
{
   long num;
   struct stud a; struct stud *p;
   FILE *fp;

   p=&a;
  
   printf("\nplease input num\n");
   scanf("%ld",&num);

   fp=fopen("student","rb");
   while(1)
  {
     fread(&a,sizeof(a),1,fp);
     if(p->num == num)
     {
        printf("%ld,%s,%5.1f,%5.1f,%5.1f\n",XXXXm,XXXXme,a.C_Score,a.M_Score,a.E_Score);
        break;
     }
     else if(num==0)
     {
         printf("num error\n");
         break;
     }
  }
       printf("......done");
  return(0);
  
}

int write()  //输入
{
    struct stud *p; struct stud a;
    FILE *fp;
    p=&a;
    
    fp=fopen("student","wb");
           printf("\nnum name C_Score M_Score E_score\n");
    while(1)
      {    

           scanf("%ld%s%f%f%f",&p->num,p->name,&p->C_Score,&p->M_Score,&p->E_Score);
           fwrite(&a,sizeof(a),1,fp);
           if(p->num==0) break;

      }
    
    fclose(fp);
    printf("......done");
  
    return(0);
}
int read()   //输出
{
   FILE *fp;
   struct stud *p; struct stud b;
   p=&b;
   fp=fopen("student","rb");

   printf("\nnum,name,C_Score,M_Score,E_score\n");

  while(1)
  {
      fread(&b,sizeof(b),1,fp);
      if(p->num==0) break;
      printf("%ld,%s%5.1f%5.1f%5.1f\n",XXXXm,XXXXme,b.C_Score,b.M_Score,b.E_Score);
  
  
  }
      
   printf("......done");
   fclose(fp);

  
  return(0);
}

int main()
{
  printf("\n****************************************************************************\n");
  printf("\n**                                 welcome                                **\n");
  printf("\n****************************************************************************\n");
while(1)
{
  int i;
  printf("\n****************************************************************************\n");
  printf("\n**                          XXXXw sheet                                   **\n");
  printf("\n**                          XXXXange sheet                                **\n");
  printf("\n**                          XXXXaxun(num)                                 **\n");
  printf("\n**                          XXXXaxun(name)                                **\n");
  printf("\n**                          XXXXngji                                      **\n");
  printf("\n**                          XXXXint sheet                                 **\n");
  printf("\n**                          7.Exit                                        **\n");
  printf("\n****************************************************************************\n");
  printf("\nplease input NO.");
  scanf("%d",&i);
  
  switch(i)
{
   case 1: write();       break;
   case 2: xiugai();       break;
   case 3: xuehaochaxun();break;
   case 4: namechaxun();  break;
   case 5: tongji();      break;
   case 6: read();        break;
   case 7: exit(0);       break;  
}
}
  return(0);
}