RK.c

#pragma warning(disable:4996)

#include <stdio.h>
#include <stdlib.h>
#include <locale.h>
#include <string.h>

struct Student {
	char surname[32];
	char group[32];
	int marks[3];
};

int main() {
	setlocale(LC_ALL, "rus");

	FILE* input = NULL;
	FILE* output = NULL;
	int num = 0, i = 0, j = 0, sizeoffile = 1;
	char surname[32];
	char group[32];
	int marks[3];
	input = fopen("ddd.dat", "rb");

	if (input) {
		fseek(input, 0, SEEK_END);
		sizeoffile = ftell(input);
		fseek(input, 0, SEEK_SET);
	}
	if (!input || sizeoffile == 0) {
		output = fopen("ddd.dat", "wb");
		printf("Введите колличество студентов: ");
		scanf_s("%d", &num);
		struct Student* students = (struct Student*)malloc(sizeof(struct Student)*num);
		printf("Вводите данные в формате (Фамилия, Группа, 3 оценки) через пробел на английском:\n");
		for (i = 0; i < num; i++) {
			scanf("%s%s%d%d%d", surname, group, &marks[0], &marks[1], &marks[2]);
			strcpy_s(students[i].surname, 32, surname);
			strcpy_s(students[i].group, 32, group);
			for (int j = 0; j < 3; j++) {
				students[i].marks[j] = marks[j];
			}
		}
		fwrite(&num, sizeof(int), 1, output);
		for (i = 0; i < num; i++) {
			fwrite(&students[i], sizeof(struct Student), 1, output);
		}
		free(students);
		fclose(output);
	}

	input = fopen("ddd.dat", "rb");
	fread(&num, sizeof(int), 1, input);
	struct Student* students = (struct Student*)malloc(sizeof(struct Student) * num);
	for (i = 0; i < num; i++)
		fread(&students[i], sizeof(struct Student), 1, input);

	fclose(input);

	for (i = 0; i < num - 1; i++) {
		for (j = i + 1; j < num; j++) {
			if (students[i].marks[0] + students[i].marks[1] + students[i].marks[3] > students[j].marks[0] + students[j].marks[1] + students[j].marks[3]) {
				struct Student temp;
				temp = students[i];
				students[i] = students[j];
				students[j] = temp;
			}
		}
	}

	printf("Отсортированные по среднему баллу: \n");
	for (i = 0; i < num; i++) {
		for (i = 0; i < num; i++) {
			printf("%s %s %d %d %d\n", students[i].surname, students[i].group, students[i].marks[0], students[i].marks[1], students[i].marks[2]);
		}
	}

	system("pause");
	return 0;
}