041.学生成绩管理程序

/*
学生成绩管理程序
编制一个统计学生考试分数的管理程序。
设学生成绩已以一个学生一个记录的形式存储在文件中，
每位学生记录包含的信息有：姓名，学号和各门功课的成绩。
程序具有以下几项功能：求出各门课程的总分，平均分，按姓名，
按学号寻找其记录并显示，浏览全部学生成绩和按总分由高到低显示学生信息等。
*/
#include <stdio.h>
#define SWN   3 /* 课程数 */
#define NAMELEN   20  /* 姓名最大字符数 */
#define CODELEN   10  /* 学号最大字符数 */
#define FNAMELEN  80  /* 文件名最大字符数 */
#define BUFLEN    80  /* 缓冲区最大字符数 */
/* 课程名称表 */
char schoolwork[SWN][NAMELEN+1] = {"Chinese","Mathematic","English"};
struct record
{
  char  name[NAMELEN+1];  /* 姓名 */
  char  code[CODELEN+1];  /* 学号 */
  int   marks[SWN];   /* 各课程成绩 */
  int total;      /* 总分 */
}stu;
struct node
{
  char  name[NAMELEN+1];  /* 姓名 */
  char  code[CODELEN+1];  /* 学号 */
  int   marks[SWN];   /* 各课程成绩 */
  int   total;      /* 总分 */
  struct  node *next;   /* 后续表元指针 */
}*head; /* 链表首指针 */
int total[SWN];   /* 各课程总分 */
FILE *stfpt;    /* 文件指针 */
char stuf[FNAMELEN];  /* 文件名 */
/* 从指定文件读入一个记录 */
int readrecord(FILE *fpt,struct record *rpt)
{
  char buf[BUFLEN];
  int i;
  if(fscanf(fpt,"%s",buf)!=1)
    return 0; /* 文件结束 */
  strncpy(rpt->name,buf,NAMELEN);
  fscanf(fpt,"%s",buf);
  strncpy(rpt->code,buf,CODELEN);
  for(i=0;i<SWN;i++)
    fscanf(fpt,"%d",&rpt->marks[i]);
  for(rpt->total=0,i=0;i<SWN;i++)
    rpt->total+=rpt->marks[i];
  return 1;
}
/* 对指定文件写入一个记录 */
writerecord(FILE *fpt,struct record *rpt)
{
  int i;
  fprintf(fpt,"%s\n",rpt->name);
  fprintf(fpt,"%s\n",rpt->code);
  for(i=0;i<SWN;i++)
    fprintf(fpt,"%d\n",rpt->marks[i]);
  return ;
}
/* 显示学生记录 */
displaystu(struct record *rpt)
{
  int i;
  printf("\nName   : %s\n",rpt->name);
  printf("Code   : %s\n",rpt->code);
  printf("Marks  :\n");
  for(i=0;i<SWN;i++)
    printf("       %-15s : %4d\n",schoolwork[i],rpt->marks[i]);
  printf("Total  : %4d\n",rpt->total);
}
/* 计算各单科总分 */
int totalmark(char *fname)
{
  FILE *fp;
  struct record s;
  int count,i;
  if((fp=fopen(fname,"r"))==NULL)
  {
    printf("Can't open file %s.\n",fname);
    return 0;
  }
  for(i=0;i<SWN;i++)
    total[i]=0;
  count=0;
  while(readrecord(fp,&s)!=0)
  {
    for(i=0;i<SWN;i++)
      total[i]+=s.marks[i];
    count++;
  }
  fclose(fp);
  return count; /* 返回记录数 */
}
/* 列表显示学生信息 */
void liststu(char *fname)
{
  FILE *fp;
  struct record s;
  if((fp=fopen(fname,"r"))==NULL)
  {
    printf("Can't open file %s.\n",fname);
    return ;
  }
  while(readrecord(fp,&s)!=0)
  {
    displaystu(&s);
    printf("\n      Press ENTER to continue...\n");
    while(getchar()!='\n');
  }
  fclose(fp);
  return;
}
/* 构造链表 */
struct node *makelist(char *fname)
{
  FILE *fp;
  struct record s;
  struct node *p,*u,*v,*h;
  int i;
  if((fp=fopen(fname,"r"))==NULL)
  {
    printf("Can't open file %s.\n",fname);
    return NULL;
  }
  h=NULL;
  p=(struct node *)malloc(sizeof(struct node));
  while(readrecord(fp,(struct record *)p)!=0)
  {
    v=h;
    while(v&&p->total<=v->total)
    {
      u=v;
      v=v->next;
    }
    if(v==h)
      h=p;
    else
      u->next=p;
    p->next=v;
    p=(struct node *)malloc(sizeof(struct node));
  }
  free(p);
  fclose(fp);
  return h;
}
/* 顺序显示链表各表元 */
void displaylist(struct node *h)
{
  while(h!=NULL)
  {
    displaystu((struct record *)h);
    printf("\n      Press ENTER to continue...\n");
    while(getchar()!='\n');
    h=h->next;
  }
  return;
}
/* 按学生姓名查找学生记录 */
int retrievebyn(char *fname, char *key)
{
  FILE *fp;
  int c;
  struct record s;
  if((fp=fopen(fname,"r"))==NULL)
  {
    printf("Can't open file %s.\n",fname);
    return 0;
  }
  c=0;
  while(readrecord(fp,&s)!=0)
  {
    if(strcmp(s.name,key)==0)
    {
      displaystu(&s);
      c++;
    }
  }
  fclose(fp);
  if(c==0)
    printf("The student %s is not in the file %s.\n",key,fname);
  return 1;
}
/* 按学生学号查找学生记录 */
int retrievebyc(char *fname, char *key)
{
  FILE *fp;
  int c;
  struct record s;
  if((fp=fopen(fname,"r"))==NULL)
  {
    printf("Can't open file %s.\n",fname);
    return 0;
  }
  c=0;
  while(readrecord(fp,&s)!=0)
  {
    if(strcmp(s.code,key)==0)
    {
      displaystu(&s);
      c++;
      break;
    }
  }
  fclose(fp);
  if(c==0)
    printf("The student %s is not in the file %s.\n",key,fname);
  return 1;
}
main()
{
  int i,j,n;
  char c;
  char buf[BUFLEN];
  FILE *fp;
  struct record s;
  clrscr();
  printf("Please input the students marks record file's name: ");
  scanf("%s",stuf);
  if((fp=fopen(stuf,"r"))==NULL)
  {
    printf("The file %s doesn't exit, do you want to creat it? (Y/N) ",stuf);
    getchar();
    c=getchar();
    if(c=='Y'||c=='y')
    {
      fp=fopen(stuf,"w");
      printf("Please input the record number you want to write to the file: ");
      scanf("%d",&n);
      for(i=0;i<n;i++)
      {
        printf("Input the student's name: ");
        scanf("%s",&s.name);
        printf("Input the student's code: ");
        scanf("%s",&s.code);
        for(j=0;j<SWN;j++)
        {
          printf("Input the %s mark: ",schoolwork[j]);
          scanf("%d",&s.marks[j]);
        }
        writerecord(fp,&s);
      }
      fclose(fp);
    }
  }
  fclose(fp);
  getchar();
  /*clrscr();*/
  puts("Now you can input a command to manage the records.");
  puts("m : mean of the marks.");
  puts("t : total of the marks.");
  puts("n : search record by student's name.");
  puts("c : search record by student's code.");
  puts("l : list all the records.");
  puts("s : sort and list the records by the total.");
  puts("q : quit!");
  while(1)
  {
    puts("Please input command:");
    scanf(" %c",&c);    /* 输入选择命令 */
    if(c=='q'||c=='Q')
    {
      puts("\n Thank you for your using.");
      break;    /* q，结束程序运行 */
    }
    switch(c)
    {
      case 'm': /* 计算平均分 */
      case 'M':
        if((n=totalmark(stuf))==0)
        {
          puts("Error!");
          break;
        }
        printf("\n");
        for(i=0;i<SWN;i++)
          printf("%-15s's average is: %.2f.\n",schoolwork[i],(float)total[i]/n);
        break;
      case 't': /* 计算总分 */
      case 'T':
        if((n=totalmark(stuf))==0)
        {
          puts("Error!");
          break;
        }
        printf("\n");
        for(i=0;i<SWN;i++)
          printf("%-15s's total mark is: %d.\n",schoolwork[i],total[i]);
        break;
      case 'n': /* 按学生的姓名寻找记录 */
      case 'N':
        printf("Please input the student's name you want to search: "); 
        scanf("%s",buf);
        retrievebyn(stuf,buf);
        break;
      case 'c': /* 按学生的学号寻找记录 */
      case 'C':
        printf("Please input the student's code you want to search: "); 
        scanf("%s",buf);
        retrievebyc(stuf,buf);
        break;
      case 'l': /* 列出所有学生记录 */
      case 'L':
        liststu(stuf);
        break;
      case 's': /* 按总分从高到低排列显示 */
      case 'S':
        if((head=makelist(stuf))!=NULL)
          displaylist(head);
        break;
      default: break;
    }
  }
}