Работа со структурой

[SorryHelpMePLZ]

#include<stdio.h>
#include"student.h"
#include <string.h>
#include <stdlib.h>
void student(struct Students *students)
    {
        printf("Students NZBook:%s\n",students->NZBook);
        printf("Students name:%s\n",students->name);
        printf("exzams:%s\n",students->examen);
        printf("marks:%i\n\n",students->marks);
    }
 
void studentsGradePointAverage(studens)
{
    
}
void All_students(struct Students *students, int c)
{
    int i;
    for(i=0;i<c;i++)
        student(&students[i]);
    getc(stdin);
}
 
 
void searchStudents(struct Students *students, int c)
 
{
    int i;
    char NZBook[20];
    printf("VVedite number zachetnoy book\n");
    scanf("%s",NZBook);
        for(i=0;i<c;i++)
    {
        if(strcmp(NZBook, students[i].NZBook)==0)
            student(&students[i]);
    }
    getc(stdin);
}
 
int print_menu ()
    {
        char *menu[]=
        {
            "All_students",
            "SearchNZBook",
            "StudentsGradePointAverage",
            "EXIT",
        };
 
        const int menuCount = sizeof menu/sizeof menu[0];
        int i;
        for (i=0; i<menuCount; i++)
        printf("%i. %s\n", i+1, menu[i]);
        return getc(stdin);
    };
    
int main()
{
    struct Students students[]=
    {
        {"10001","Ronaldo","Russ",4},
        {"10001","Ronaldo","Ukrain",2},
        {"10001","Ronaldo","Fvs",5},
        {"10002","Messi","English,",5},
        {"10002","Messi","Ukrain",5},
        {"10002","Messi","Russ",5},
        {"10003","Ves","Mathemat",3},
        {"10003","Ves","FVS",5},
        {"10003","Ves","Histori",3},
        {"10004","Mark","Russ",5},
        {"10004","Mark","FVS",5},
        {"10004","Mark","English",5},
    };
    int r;
    printf("----MENU----\n");
    while((r=print_menu())!='5')
    switch(r) 
    {
        case '1': All_students(students, sizeof students /sizeof (struct Students));break;
        case '2': searchStudents(students,sizeof students/sizeof(struct Students));break;
        case '3': studentsGradePointAverage(students);break;
        case '4': printf("EXIT,\n"); break;
        case '5': break;
    }
    return 0;
}

Структура

struct Students
{
    char NZBook[20];
    char name[100];
    char examen[100];
    int marks; //"1","2","3","4","5";
};

помогите вставить часть программы, а то я совсем не понимаю куда ее пихать. Заранее благодарен

struct Examen
{
    char name[25];
    int mark; // 1-5
};
 
struct Students
{
    char NZBook[20];
    char name[100];
    struct Examen e[5];
    double calcAveMark() const
    {
        int sum = 0, i;
        for (i=0; i < 5; i++)
            sum += e[i].mark;
 
        return sum / 5.0;
    }
};

[SorryHelpMePLZ]

помогите записать в файл это все