#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int stack_create (int * * st, int n, int * curr, int * head, int * tail);
int stack_delete (int * st, int n, int * curr, int * head, int * tail);
int stack_append (int * st, int n, int * curr, int * head, int * tail, int el);
int stack_delete_el (int * st, int n, int * curr, int * head, int * tail);
int stack_read (int * st, int n, int * curr, int * head, int * tail, int * previous);
int stack_print (int * st, int n, int * curr, int * head, int * tail);

int stack_create (int * * st, int n, int * curr, int * head, int * tail) {
    if (*curr != -1 )
        return -1;
    if (n <= 0)
        return -1;
    *st = (int *) malloc(n*sizeof(int));
    if (*st == NULL)
        return -1;
    *curr = 0;
    *head = 0;
    *tail = 0;
    return 0;
}
int stack_delete (int * st, int n, int * curr, int * head, int * tail) {
    if (st == NULL)
        return -1;
        free(st);
        *curr = -1;
        return 0;
}
int stack_append (int * st, int n, int * curr, int * head, int * tail, int el) {
    if (*curr == -1)
        return -1;
    if (*curr == n)
        return -1;
    st[*tail] = el;
    *tail = (*tail+1) % n;
    *curr = *curr + 1;


    return 0;
}
int stack_delete_el (int * st, int n, int * curr, int * head, int * tail) {

    if (*curr == -1)
        return -1;
    if (*curr == 0)
        return -1;
    *head = (*head+1) % n;
    *curr = *curr - 1;
    return 0;
}
int stack_read (int * st, int n, int * curr, int * head, int * tail, int * previous) {
    if (*curr == -1)
        return -1;
    if (*curr == 0)
        return -1;
    *previous = st[*tail];
    return 0;
}
int stack_print (int * st, int n, int * curr, int * head, int * tail) {
    if (*curr == -1)
        return -1;
    int curr_local, empty;
    curr_local = *curr;
    if (curr_local == 0 ) {
        for (int i = 0; i < n; i++)
        printf("*\n");
        return 0;
    }
    if (*curr == n)
        empty = 0;
    else
        empty = n-curr_local;
    int i;
    i = *head;
    while ((i < n) && (curr_local > 0)) {
        printf("%d\n", st[i]);
        i++;
        curr_local--;
    }
    i = 0;
    while ((i <=(*tail)) && (curr_local > 0)) {
        printf("%d\n", st[i]);
        i++;
        curr_local--;
    }
    for (int i = 0; i < empty; i++)
        printf("*\n");
    return 0;
}


int main() {
    int * st;
    int curr, head, tail, N, el, a;
    curr = -1;
    head = -1;
    tail = -1;
    int choice, code;
    st = NULL;
    while (1) {
        printf("Select value: \n");
        printf("1 - create stack\n");
        printf("2 - delete stack\n");
        printf("3 - append element to stack\n");
        printf("4 - delete element from stack\n");
        printf("6 - print stack\n");
        scanf("%d", &choice);
        switch (choice) {
            case 1:
                printf("Enter number of elements: ");
                scanf("%d", &N);
                printf("\n");
                code = stack_create(&st, N, &curr, &head, &tail);
                if (code == -1) printf("Forbidden\n");
                break;
            case 2:
                code = stack_delete(st, N, &curr, &head, &tail);
                if (code == -1) printf("Forbidden\n");
                break;
            case 3:
                printf("Enter element to be appended: ");
                scanf("%d", &el);
                printf("\n");
                code = stack_append(st, N, &curr, &head, &tail, el);
                if (code == -1) printf("Forbidden\n");
                break;
            case 4:
                code = stack_delete_el(st, N, &curr, &head, &tail);
                if (code == -1) printf("Forbidden\n");
                break;
            case 5:
                code = stack_read(st, N, &curr, &a, &head, &tail);
                if (code == -1) printf("Forbidden\n");
                break;
            case 6:
                code = stack_print(st, N, &curr, &head, &tail);
                if (code == -1) printf("Forbidden\n");
                break;
            default:
                printf("Wrong Choice!\n");
                break;
        }



    }
    return 0;
}