Students

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

struct student
{
    char name[100];
    char scname[100];
    char o[100];
    int gr;
    int mark[5];
};

struct student group[100];

void printstudent(int j){
    printf("Student #%d: %s %s %s\n", j + 1, group[j].scname, group[j].name, group[j].o);
    printf("Group: %d\nMarks: ", group[j].gr);
    float s = 0;
    for (int q = 0; q< 5; q++){
        printf("%d ", group[j].mark[q]);
        s += group[j].mark[q];
    }
    printf("\nAverage: %f\n", s / 5.0);
}

int main()
{
    FILE * file = fopen("in.txt", "r");

    int i = 0;
    while (fscanf (file, "%s%s%s%d%d%d%d%d%d", group[i].name, group[i].scname, group[i].o,
                 &(group[i].gr), &(group[i].mark[0]),
                 &(group[i].mark[1]), &(group[i].mark[2]),
                 &(group[i].mark[3]),  &(group[i].mark[4])) != EOF) {
        i++;
    }

    for (int j = 0; j < i; j++){
        printstudent(j);
    }

    int f;
    printf("\nEnter number of a student, or -1 to exit: ");
    scanf("%d", &f);
    while (f != -1){
        if (f > 0 && f <= i){
            f--;
            printstudent(f);
        } else{
            printf("Error\n");
        }

        printf("Enter number of a student, or -1 to exit: ");
        scanf("%d", &f);
    }

    return 0;
}