#include <stdio.h>
typedef struct list
{
    char sur[128];
    int  ball;
    int  mark;
}list;
int swap(const void *a,const void *b);
int addstud(char *std);
int sortstud(char *std);

int main()
{
 list stud;
 int i=0,menu,t=0;
 float n=0;
 char std[] = "stud.txt";
 FILE *fl;

 while (1)
 {
    printf("1)Add new studentn2)Show list of studentsn3)Change info about studentn4)Delete studentn5)Exitn");
    scanf("%d",&menu);
    switch (menu)
    {
 case 1:
        addstud(std);
        break;
 case 2:
        viewinfo(std);
        break;
case  3:
        sortstud(std);
        break;
 case 4:
        delstud(std,n,t);
        t++;
        break;

 case 5:

        return 0;
 default:
        printf("Eror, please try again!n");
        //system("cls");
    }

 }
}

int addstud(char *std)
{
    FILE *fl;
    fl  = fopen(std, "a");
    list stud;
    if (fl == 0)
    {
        fprintf(stderr, "Error open filen");
        return 1;
    }
    printf("Enter surname student: ");
    scanf("%s",stud.sur);
    //printf("%s",stud.sur);
    //fprintf(fl,"%-9s",stud->sur);
    printf("Enter scores of student: ");
    scanf("%d",&stud.ball);
    //printf("%d",stud.ball);
    //fprintf(fl,"%-4d",stud->ball);
    stud.mark = 0;
    fwrite(&stud,sizeof(list),1,fl);
    printf("n");
    //fprintf(fl,"%-4dn",stud->mark);
    fclose(fl);
    printf("Press Enter for continue...n");
    //getch();
    //system("cls");
    return(0);
}

int sortstud(char *std)
{
    FILE *fl;
    int j = 0,i = 0, n = 0;
    list stud[10];
    int temp;
    list studt;
    fl = fopen(std,"r+b");
    fseek(fl,0,SEEK_END);
    long size = ftell(fl);
    fseek(fl,0,SEEK_SET);
    int sizefile = sizeof(list);
    n = (size/sizefile);
    qsort(stud,n,sizeof(list),swap);
 fclose(fl);
}
int swap(const void *a,const void *b)
{
    return ((list*)a)->ball  ((list*)b)->ball;
}