#include <stdio.h>
#include <stdlib.h>
#define MAX 5

typedef struct red{
    int niz[MAX];
    int f, r;
} RED;

typedef struct cvor{
    int a;
    struct cvor *sljedeci;
} CVOR;

int isFull(RED *bafer)
{
    return (bafer->r + 1) % MAX == bafer->f;
}

int isEmpty(RED *bafer)
{
    return bafer->f == -1;
}

int dodaj(RED *bafer, int podatak)
{
    if (isFull(bafer)) return 0;
    if (bafer->f == -1) bafer->f = 0;
    bafer->r = (bafer->r + 1) % MAX;
    bafer->niz[bafer->r] = podatak;
    return 1;
}

int brisi(RED *bafer, int *podatak)
{
    if (isEmpty(bafer)) return 0;
    *podatak = bafer->niz[bafer->f];
    if (bafer->f == bafer->r) bafer->f = bafer->r = -1;
    else bafer->f = (bafer->f + 1) % MAX;
    return 1;
}

int pisi(RED *bafer)
{
    if (isEmpty(bafer)) return 0;
    int i = bafer->f;
    if (bafer->f <= bafer->r)
        while (i <= bafer->r) printf("%d ", bafer->niz[i++]);
    else
    {
        while (i <= MAX - 1) printf("%d ", bafer->niz[i++]);
        i = 0;
        while (i <= bafer->r) printf("%d ", bafer->niz[i++]);
    }
    return 1;
}

void push(CVOR **tos, int *t)
{
    CVOR *novi = (CVOR*)malloc(sizeof(CVOR));
    novi->a = *t;
    novi->sljedeci = *tos;
    *tos = novi;
}

int pop(CVOR **tos, int *t)
{
    if (*tos == 0) return 0;
    CVOR *p = *tos;
    *t = p->a;
    *tos = p->sljedeci;
    free(p);
    return 1;
}

int main()
{
    RED bafer;
    bafer.f = bafer.r = -1;
    char c;
    int broj;
    CVOR *tos = 0;
    do{
        printf("===================================================\n");
        printf("Dodavanje[D], brisanje [B], prikaz [P], kraj [0]? ");
        scanf("\n%c", &c);
        if (c == 'D')
        {
            printf("  Unesite broj: ");
            scanf("%d", &broj);
            push(&tos, &broj);
            if (dodaj(&bafer, broj) == 0) printf("  Bafer je pun!\n");
        }
        else if (c == 'B')
        {
            if (brisi(&bafer, &broj)) printf("  Obrisan je broj: %d\n", broj);
            else printf("  Bafer je prazan!\n");
        }
        else if (c == 'P')
        {
            printf("  Sadrzaj bafera: ");
            if (pisi(&bafer) == 0) printf("\n  Bafer je prazan!\n");
            else printf("\n");
        }
        else if (c != '0') printf("  Nepoznata opcija - '%c'.\n", c);
    }
    while (c != '0');
    while(pop(&tos,&broj)) printf("%d ", broj);
    return 0;
}