load_file sort_list print_average

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct dt dt;
struct dt {
  int student;
  char course[20];
  int score;
  dt *next;
};
static dt *head;
static void load_file(void) {
  FILE *file = fopen("data.txt", "r");
  int s;
  char c[20];
  int sc;
  head = NULL;
  while (fscanf(file, "%d%s%d", &s, c, &sc) != EOF) {
    dt *new = calloc(sizeof(*new), 1);
    new->student = s;
    strcpy(new->course, c);
    new->score = sc;
    new->next = head;
    head = new;
  }
}
static void show_dt(void) {
  for (dt *p = head; p; p = p->next) {
    printf("%d %s %d\n", p->student, p->course, p->score);
  }
}
static void remove_one(dt *d) {
  if (head == d) {
    head = head->next;
    return;
  }
  for (dt *p = head->next, *prev = head; p; prev = p, p = p->next) {
    if (p == d) {
      prev->next = p->next;
      return;
    }
  }
}
static void sort_list(void) {
  if (!head) {
    return;
  }
  dt *min = head;
  for (dt *p = head->next; p; p = p->next) {
    if (p->student < min->student) {
      min = p;
    }
  }
  remove_one(min);
  sort_list();
  min->next = head;
  head = min;
}
static void print_average(void) {
  int count = 0, total = 0;
  for (dt *p = head; p; p = p->next) {
    ++count;
    total += p->score;
    if (p->next && p->next->student == p->student) {
      continue;
    }
    printf("%d %d %d\n", p->student, count, total / count);
    count = total = 0;
  }
}
int main(void) {
  load_file();
  sort_list();
  print_average();
}