=)(P.S. Если что пишите)

// Задание 6.2(16) Стельмашук В.А.(гр. №953506)

/*Рейтинг студентов.
Программа рассчитывает рейтинг студентов
специальности «Информатика».Рейтинг учитывает все оценки,
полученные студентами во время сессий – как положительные, так
и отрицательные.Можно просмотреть рейтинг по курсам, по
группам.Отображается текущий средний балл, рост
(положительный или отрицательный) относительно последней
сессии, изменение места в рейтинге.*/


#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include <string.h>


typedef struct student
{
    char* surname;
    char* name;
    char* patronym;
    int course;
    int group;
    int* marks1, *marks2; /*оценки за две сессии*/
    double average1, average2; /*средний балл за две сессии*/

    int ratingPlace1, ratingPlace2; /*место в рейтинге в первой и во второй сессии*/
    double averageDelta; /*изменение среднего балла относительно последней сессии*/
    int ratingDelta; /*изменение места в рейтинге*/
} Student;

typedef struct node
{
    int number;
    Student* student;
    struct node* next;// указатель на следующий эл. списка
    struct node* prev;// указатель на предыдущий эл. списка
} Node;

typedef struct list
{
    Node* first, *last;
    int counter;
} List;

List* list;
int updated = 0;

void FreeMemoryNode(node* &Node);
void FreeMemoryList(List* &LIST);
void Menu(void);
int chooseOption(void);

void showStudent(Student* student, int sem);
void showList(int sem);
void showByGroup(int group);
void showByCourse(int course);
void QuickSortList(Node* left, Node* right);

double getAverage(int** marks);
double getAverageDelta(Student* student);
int getRatingDelta(Node* node);
void update(void);

char* readString(FILE* file);
int* readDigit(FILE* file);
Student* readStudent(FILE* file);
void pushBack(Student* student);
void writeStudent(Student* student, FILE* file);

void save();

int main()
{
    list = (List*)malloc(sizeof(List));
    list->first = NULL;
    list->last = NULL;
    list->counter = 0;

    FILE* students = fopen("C:\\Лабораторные С\\LR7\\students.txt", "r");
    if (students == NULL)
    {
        printf("\nSomething is wrong. File wasn't open :<");
        return 0;
    }

    while (!feof(students))
        pushBack(readStudent(students));

    while (1)
        Menu();

    fclose(students);
    return 0;
}

void FreeMemoryNode(node* &Node)
{
    free(Node->student->surname);
    free(Node->student->name);
    free(Node->student->patronym);
    free(Node->student->marks1);
    free(Node->student->marks2);
    free(Node->student);
    free(Node);
}

void FreeMemoryList(List* &LIST)
{
    if (LIST->first != NULL)
    {
        node* current = LIST->first;
        while (current != LIST->last)
        {
            current = current->next;
            if (current != LIST->last)
                FreeMemoryNode(current->prev);
        }
        free(current);
        LIST->first = NULL;
        LIST->last = NULL;
        LIST->counter = 0;
    }
}

void Menu(void)
{
    printf("\t\t\t\t\t\tMenu");
    printf("\n\t\t\t\t\t1. Show first semester rating");
    printf("\n\t\t\t\t\t2. Update on the results of the second semester");
    printf("\n\t\t\t\t\t3. Show second semester rating");
    printf("\n\t\t\t\t\t4. Show all information");
    printf("\n\t\t\t\t\t5. Show specific course..");
    printf("\n\t\t\t\t\t6. Show specific group..");
    printf("\n\t\t\t\t\t7. Exit from the program");
    chooseOption();
}

int chooseOption(void)
{
    int ans = 0;

    printf("\nYour choice: ");
    while (!scanf("%d", &ans) || ans <= 0 || ans > 7)
    {
        printf("Wrong input! Try again. \n");
        while (getchar() != '\n');
        printf("\nYour choice: ");
    }
    while (getchar() != '\n');

    switch (ans)
    {
    case 1:
        showList(1);
        break;
    case 2:
        QuickSortList(list->first, list->last);
        update();
        system("cls");
        printf("\n\nRating was updated!\n\n");
        break;
    case 3:
        showList(2);
        break;
    case 4:
        showList(0);
        break;
    case 5:
    {
        int course = 0;
        printf("\nEnter number of a course: ");
        while (!scanf("%d", &course) || course < 0)
        {
            printf("Wrong input! Try again. \n");
            while (getchar() != '\n');
            printf("\nEnter number of a course: ");
        }
        while (getchar() != '\n');

        showByCourse(course);
        break;
    }
    case 6:
    {
        int group = 0;
        printf("\nEnter number of a group: ");
        while (!scanf("%d", &group) || group < 0)
        {
            printf("Wrong input! Try again. \n");
            while (getchar() != '\n');
            printf("\nEnter number of a group: ");
        }
        while (getchar() != '\n');

        showByGroup(group);
        break;
    }
    case 7:
        save();
        printf("\nGood bye!\n\n");
        exit(1);
    default:
        printf("\nSomething is wrong!");
    }

    return ans;
}

void showStudent(Student* student, int sem)
{
    printf("\n%s ", student->surname);
    printf("%s ", student->name);
    printf("%s", student->patronym);

    printf("\nCourse: %d", student->course);
    printf("\nGroup: %d", student->group);

    int k = 0;
    if (sem == 1 || sem == 0)
    {
        printf("\nFirst semester marks: ");
        for (k = 0; k < 4; k++)
            printf("%d ", student->marks1[k]);

        printf("\nRating place in first semester: %d", student->ratingPlace1);

        printf("\nAverage point in first semester: %.2f", student->average1);
    }
    if (sem == 2 || sem == 0)
    {
        if (updated == 1)
        {
            printf("\nSecond semester marks: ");
            for (k = 0; k < 4; k++)
                printf("%d ", student->marks2[k]);

            printf("\nRating place in second semester: %d", student->ratingPlace2);

            printf("\nRating increase: ");
            if (student->ratingDelta > 0)
                printf("+");
            printf("%d", student->ratingDelta);

            printf("\nAverage in second semester: %.2f", student->average2);

            printf("\nAverage point increase: ");
            if (student->averageDelta > 0)
                printf("+");
            printf("%.2f", student->averageDelta);
        }
        else
            printf("\nTo see more information firstly update rating");
    }

    printf("\n\n");
}

void showList(int sem)
{
    system("cls");

    Node* current = list->first;

    if (list->first == NULL)
        printf("The list is empty :(");
    else
    {
        while (current != NULL)
        {
            showStudent(current->student, sem);
            current = current->next;
        }
    }
}

void showByCourse(int course)
{
    system("cls");

    Node* current = list->first;

    int done = 0;

    if (list->first == NULL)
        printf("The list is empty :(");
    else
    {
        while (current != NULL)
        {
            if (current->student->course == course)
            {
                showStudent(current->student, 0);
                done = 1;
            }
            current = current->next;
        }
    }

    if (done == 0)
        printf("\n\nNo matches found :(\n\n");
}

void showByGroup(int group)
{
    system("cls");

    Node* current = list->first;

    int done = 0;

    if (list->first == NULL)
        printf("The list is empty :(");
    else
    {
        while (current != NULL)
        {
            if (current->student->group == group)
            {
                showStudent(current->student, 0);
                done = 1;
            }
            current = current->next;
        }
    }

    if (done == 0)
        printf("\n\nNo matches found :(\n\n");
}

void QuickSortList(Node* left, Node* right)
{
    if (list->first == NULL)
        return;

    Node* start;
    Node* current;
    Student* placeholder;

    if (left == right)
        return;

    start = left;
    current = start->next;

    while (1)
    {
        if (start->student->average2 > current->student->average2)
        {
            placeholder = current->student;
            current->student = start->student;
            start->student = placeholder;
        }

        if (current == right)
            break;

        current = current->next;
    }

    placeholder = left->student;
    left->student = current->student;
    current->student = placeholder;

    Node* oldCurrent = current;

    current = current->prev;

    if (current != NULL)
        if ((left->prev != current) && (current->next != left))
            QuickSortList(left, current);

    current = oldCurrent;
    current = current->next;

    if (current != NULL)
        if ((current->prev != right) && (right->next != current))
            QuickSortList(current, right);
}

double getAverage(int** marks)
{
    double sum = 0;
    int amount = 0;
    int i = 0;

    for (i = 0; (*marks)[i] != NULL; i++)
        amount += 1;
    for (i = 0; i < amount; i++)
        sum += (*marks)[i];

    return sum / amount;
}

double getAverageDelta(Student* student)
{
    return student->average2 - student->average1;
}

int getRatingDelta(Node* node)
{
    return node->student->ratingPlace1 - node->student->ratingPlace2;
}

void update(void)
{
    updated = 1;
    Node* current = list->first;

    while (current != NULL)
    {
        current->student->ratingPlace2 = current->number + 1;
        current->student->ratingDelta = getRatingDelta(current);
        current->student->averageDelta = getAverageDelta(current->student);
        current = current->next;
    }
}

Student* readStudent(FILE* file)
{
    Student* newStudent = (Student*)malloc(sizeof(Student));

    newStudent->surname = readString(file);
    newStudent->name = readString(file);
    newStudent->patronym = readString(file);
    newStudent->course = *(readDigit(file));
    newStudent->group = *(readDigit(file));
    newStudent->marks1 = readDigit(file);
    newStudent->marks2 = readDigit(file);

    newStudent->average1 = getAverage(&(newStudent->marks1));
    newStudent->average2 = getAverage(&(newStudent->marks2));
    newStudent->averageDelta = 0;
    newStudent->ratingPlace1 = 0;
    newStudent->ratingPlace2 = 0;
    newStudent->ratingDelta = 0;

    return newStudent;
}

void pushBack(Student* student)
{
    Node* newNode = (Node*)malloc(sizeof(Node));
    newNode->next = NULL;
    newNode->student = student;
    newNode->number = list->counter;
    newNode->student->ratingPlace1 = newNode->number + 1;

    if (list->first == NULL)
    {
        list->first = newNode;
        list->last = newNode;
    }
    else
    {
        list->last->next = newNode;
        newNode->prev = list->last;
        list->last = newNode;
    }

    list->counter += 1;
}

char* readString(FILE* file)
{
    char s[100];
    fscanf(file, "%s", s);
    int len = strlen(s);

    char* output = (char*)calloc(len + 1, sizeof(char));
    if (output == NULL)
    {
        printf("\nNot enough memory :(");
        exit(1);
    }

    strcpy(output, s);

    return output;
}

int* readDigit(FILE* file) /*считывание строки с оценками*/
{
    int* vals = (int*)calloc(100, sizeof(int)); /*массив значений*/

    char s[30] = "";
    fscanf(file, "%s", s);

    int col = 0;
    int i = 0;
    for (i = 0; s[i] != '\0'; i++)
    {
        if (s[i] == ' ' || s[i] == '\t' || s[i] == ',')
            continue;

        if (s[i] == '-' || (s[i] >= '0' && s[i] <= '9'))
        {
            char* box = (char*)calloc(5, sizeof(char));
            int len = 0;
            while (s[i] == '-' || (s[i] >= '0' && s[i] <= '9'))
            {
                box[len++] = s[i];
                i++;
            }
            vals[col++] = atoi(box);
        }
    }
    return vals;
}

void save()
{
    FILE* file;
    file = fopen("C:\\Лабораторные С\\LR7\\studentsOutput.txt", "w");

    Node* current = list->first;

    while (current != NULL)
    {
        writeStudent(current->student, file);
        current = current->next;
    }
    fclose(file);
}

void writeStudent(Student* student, FILE* file)
{
    fprintf(file, "\n%s ", student->surname);
    fprintf(file, "%s ", student->name);
    fprintf(file, "%s", student->patronym);

    fprintf(file, "\nCourse: %d", student->course);
    fprintf(file, "\nGroup: %d", student->group);

    fprintf(file, "\nFirst semester marks: ");
    int k = 0;
    for (k = 0; k < 4; k++)
        fprintf(file, "%d ", student->marks1[k]);

    fprintf(file, "\nRating place in first semester: %d", student->ratingPlace1);

    fprintf(file, "\nAverage point in first semester: %.2f", student->average1);

    if (updated == 1)
    {
        fprintf(file, "\nSecond semester marks: ");
        for (k = 0; k < 4; k++)
            fprintf(file, "%d ", student->marks2[k]);

        fprintf(file, "\nRating place in second semester: %d", student->ratingPlace2);

        fprintf(file, "\nRating increase: ");
        if (student->ratingDelta > 0)
            fprintf(file, "+");
        fprintf(file, "%d", student->ratingDelta);

        fprintf(file, "\nAverage in second semester: %.2f", student->average2);

        fprintf(file, "\nAverage point increase: ");
        if (student->averageDelta > 0)
            fprintf(file, "+");
        fprintf(file, "%.2f", student->averageDelta);
    }

    fprintf(file, "\n\n");
}