Teacher* Teacher_to_aar(int num)
{
    FILE *Th;
    Teacher *tch;
    char chk[2]={'a'}, buffer[500],buffer2[500],buffer3[500],buffer4[500],Code[500];
    int Mhr,Ehr,tmp,i=0;

    Th = fopen("Teacher.txt","r");
    if (Th == NULL) Get_Lost("Can't open Teacher.txtn");
    tch=(Teacher*)malloc(sizeof(Teacher)*num);
    if (tch == NULL)
        Get_Lost("Allocation failed");
    while(strcmp(chk,";") != 0)
        fscanf(Th,"%c",chk);
    for(i=0;i<num;i++)
    {
        fscanf(Th,"%s %s %s %s %s %d %d", Code, buffer,buffer2,buffer3,buffer4,&(tch[i].mHours),&(tch[i].eHours));
        tmp=strlen(buffer);     // First name
        tch[i].fname = (char*)malloc(tmp);
        strcpy(tch[i].fname,buffer);
        tmp=strlen(buffer2);        // Last name
        tch[i].lname = (char*)malloc(tmp);
        strcpy(tch[i].lname,buffer2);
        tmp=strlen(buffer3);        // Title
        tch[i].title = (char*)malloc(tmp);
        strcpy(tch[i].title,buffer3);
        tmp=strlen(buffer4);        // Prefrence
        tch[i].pref = (char*)malloc(tmp);
        strcpy(tch[i].pref,buffer4);
        tmp=strlen(Code);       // Serial
        tch[i].serial = (char*)malloc(tmp);
        strcpy(tch[i].serial,Code);
        }
}

fscanf(Th,"%c",chk);

Main: malloc.c:2395: sysmalloc: Assertion `(old_top == initial_top (av) && old_size == 0) || ((unsigned long) (old_size) >= MINSIZE && prev_inuse (old_top) && ((unsigned long) old_end & (pagesize - 1)) == 0)' failed.

Program received signal SIGABRT, Aborted.
0x00007ffff773a418 in __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:54
54  ../sysdeps/unix/sysv/linux/raise.c: No such file or directory.