Void pointer to struct pointers.Prob when putting the address in the void pointer

Question

I got a void **stack which contains the addresses of the struct pointers my problem is that when I print the whole stack different addresses are shown than the actual addresses I'm actually trying to save in the stack.

I've tested if stud_input works correctly by printing the content of the struct and it seems to work fine.

I normally have 1 more struct(struct professor) but I got the same prob for both so I'm not posting both to make it less complicated.

example of what I expect to be printed vs what I really get when I print the addresses

Expected:

5836544 
5836851 
5837158

What i really get:

5836544
5836545
5836546

part of the code

struct student
{
    char flag;
    char surname[256];
    int semester;
};

main()
{

    struct student *stud;
    //....
    menu(stack,stackcopy,reversedstack,&prof,&stud,stacksize,&head);
    //....


}

void menu(void **stack,void **stackcopy,void **reversed,struct professor **ptr1,struct student **ptr2,int size,int *head)
{
     //....
     input(stack,ptr1,ptr2,size,head,&a,&b);
     //.....
}

int input(void **stack,struct professor **ptr1,struct student **ptr2,int size,int     *head,int *a,int *b)
{
    // *a and *b are variables that increase by one each time a student registration happens to change the add of the struct pointer every time
    int i,done=0,stud_or_prof=-1;
    //....
    *(ptr2+*a)=(struct student *)malloc(sizeof(struct student));
    done=Push(stack,head,(*(int *)ptr2+*a),size);

    if (done==1)
        stud_input(ptr2,a);
    else
        free(*(ptr2+*a));
    //...
}

int Push(void **stack,int *H,int element,int size)
{
    if (*H==(size))
        return 0;

    *((int *)stack+*H)=element;
    (*H)++;

    return 1;
}