编程实现将用户从键盘上随机输入的30和学生的学号、姓名、数学成绩、计算机成绩及总分写入数据文件score中，假设30个学生的学号从1~30连续。输入时不必按学号顺序进行，程序自动按学号顺序将输入的数据写入文件。

大家一起来做啊 ！！！

呵呵，终于通过运行了：） 说来惭愧，我学习C语言已经有两年了（断断续续，同时在看C++，Java），自己感觉学得还可以，所以认为这个题目应该很简单。结果昨天花了一晚上也没有搞定（因为很长时间没有使用C了，所以在指针理解上出了问题，一个链表总是不能正确连接，看来要真正掌握C语言的指针确实要花功夫。），今天早上再看了看才把程序做好： 我的程序由三个文件组成：list.h, list.c, main.c（在VC, Dev-C++中建立一个工程然后把文件加进去就可以运行了）

还有一个问题是在结构体中的学号（id），经过保存，读取这个过程之后结果会变不正确。（估计是个X86计算机的体系结构有关系，不知哪位大虾能解释一下。）

下面是源程序：

/* list.c */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include \"list.h\"

Student *head = NULL;  /* the head of the list */
void createList(void)
{
  /* The first node doesn't contain useful data */
  head = (Student *)malloc(sizeof(Student));
  if(head)
    head->next = NULL;
  else {
    printf(\"Memory Access Failed!\n\");
    exit(1);
  }
}
void addNode(void)
{
  Student *ptr, *pre;
  Student *temp = (Student *)malloc(sizeof(Student));
  if(temp) {
    printf(\"\nStudent ID: \");
    scanf(\"%d\", &temp->id);
    printf(\"Name: \");
    scanf(\"%s\", temp->name);
    printf(\"Math. Score: \");
    scanf(\"%d\", &temp->math);
    printf(\"Computer Score: \");
    scanf(\"%d\", &temp->computer);
    temp->next = NULL;
  } else {
    printf(\"Memory Access Failed!\n\");
    exit(1);
  }
  pre = head;
  ptr = head->next;
  while(ptr) {  /* find the right place to insert */
    if(temp->id > ptr->id) {
      pre = ptr;
      ptr = ptr->next;
    } else 
      break;
  } 
  if(ptr == NULL)  /* insert at last */
    pre->next = temp;
  else {           /*insert in the middle */
    pre->next = temp;
temp->next = ptr;
  }
}
void saveList(void)
{
  FILE *fp;
  Student *ptr = head->next;
  fp = fopen(\"score\", \"wb\");
  if(fp == NULL) {
    printf(\"Can not open file!\n\");
    exit(1);
  }
  while(ptr) {
    if(fwrite(ptr, sizeof(Student), 1, fp) == 1)
      ptr = ptr->next;
else {
   printf(\"File write error!\n\");
   exit(1);
}
  }
  
  fclose(fp);
}
void readList(void)
{
  FILE *fp;
  Student *ptr, *pre;
  fp = fopen(\"score\", \"rb\");
  if(fp == NULL) {
    printf(\"Can not open file!\n\");
    exit(1);
  }
  head = (Student *)malloc(sizeof(Student));
  if(head == NULL) {
    printf(\"Memory Access failed!\n\");
    exit(1);
  } else
    head->next = NULL;
  pre = head;
  ptr = (Student *)malloc(sizeof(Student));
  if(ptr == NULL) {
    printf(\"Memory Access Failed\n\");
    exit(1);
  } else
    ptr->next = NULL;
  while(fread(ptr, sizeof(Student), 1, fp) == 1) {
    pre->next = ptr;
    pre = ptr;
    ptr = (Student *)malloc(sizeof(Student));
    if(ptr == NULL) {
      printf(\"Memory Access Failed!\n\");
      exit(1);
    } else
      ptr->next = NULL;
  }
  fclose(fp);
}
void displayList(void)
{
  Student *ptr = head->next;
  printf(\"\n=================================\n\");
  printf(\"====  The Students' Message  ====\n\");
  printf(\"=================================\n\");    
  while(ptr) {
    printf(\"\nStudnet ID: %d\n\", ptr->id);
    printf(\"Name: %s\n\", ptr->name);
    printf(\"Math. Score: %d\n\", ptr->math);
    printf(\"Computer Score: %d\n\", ptr->computer);
    ptr = ptr->next;
  }
}
void clearList(void)
{
  Student *pre = head;
  Student *ptr;
  while(pre) {
    ptr = pre->next;
    free(pre);
    pre = ptr;
  }
}
int isEmpty(void)
{
  return (head == NULL) ? 1 : 0;
}

[此贴子已经被作者于2004-07-25 12:13:13编辑过]

还有两个文件：

/* list.h */

/* This file contains the basic data structures and the fuction declarations
   that will be used in other files. */
/* The struct represents a student */
typedef struct node
{
  int id;
  char name[20];
  int math;
  int computer;
  struct node *next;
} Student;
/* create the list */
void createList(void);
/* add a node to the list */
void addNode(void);
/* save the data to hard disk */
void saveList(void);
/* clear the list */
void clearList(void);
/* read the data from disk */
void readList(void);
/* display the list */
void displayList(void);
/* whether the list is empty */
int isEmpty(void);

/* main.c */
#include <stdio.h>
#include \"list.h\"
int menu(void)
{
  int choice;
  printf(\"\n-----------MENU----------\n\");
  printf(\"1 - Add a student's data\n\");
  printf(\"2 - Save the data\n\");
  printf(\"3 - Display the data\n\");
  printf(\"4 - Quit\n\");
  printf(\"Enter your choice: \");
  scanf(\"%d\", &choice);
  return choice;
}
int main(void)
{
  int choice;
  createList();
  choice = menu();
  while(choice != 4) {
    switch(choice) {
    case 1:
      addNode();
      break;
    case 2:
      saveList();
      clearList();
      break;
    case 3:
      if(isEmpty()) {
        readList();
        displayList();
      } else
        displayList();
      break;
    case 4:
      break;
    default:
      printf(\"Wrong input!\n\");
      break;
    }
    choice = menu();
  }
  if(!isEmpty())
    clearList();
  return 0;
}

[此贴子已经被作者于2004-07-25 12:15:33编辑过]

帮我看看这个程序有没有错误的地方 谢谢各位 ！！！

#include <stdio.h>

main()

{ FILE *fp;

struct st

{ int number;

char name[20];

float math;

float computer;

float total;

} student;

int i,j;

if((fp=fopen("score","wb+"))==NULL)

{ printf("file open error\n");

exit(0);

}

for(i=0;i<30;i++)

{ scanf("%d,%20s,%f,%f",

&student.number,student.name,&student.math,&student.computer);

student.total=student.math+student.computer;

j=student.number-1;

fseek(fp,(long)j*sizeof(struct st),SEEK_SET);

if(fwrite(&student,sizeof(student),1,fp)!=1) printf("write file error\n");

}

fclose(fp);

}

[此贴子已经被作者于2004-07-26 17:36:19编辑过]