#include "stack.h"

bool InitStack(Stack * s) {
    s->base = (int *) malloc (sizeof(int) * MAXIMUM);

    if (!s->base) {
        fprintf(stderr,"Create stack error!\n");
        return false;
    }
    s->top = s->base;
    s->size = MAXIMUM;
    
    return true;
}

bool DestroyStack(Stack * s) {
    if (!s->base){
        fprintf(stderr,"Stack not initialize!\n");
        return false;
    }
    free(s->base);

    return true;
}

bool Push(Stack * s, int n) {
    if (s->top - s->base == s->size) {
        fprintf(stderr,"Stack is full!\n");
        return false;
    }
    *s->top++ = n;  // *s->top = n; *s->top++;

    return true;
}

bool Pop(Stack * s, int * n) {
    if (s->top == s->base) {
        fprintf(stderr,"Empty stack!\n");
        return false;
    }
    *n = *--s->top; // --s->top; *n = *s->top;

    return true;
}

int GetTop(Stack * s) {
    if (s->top != s->base)
        return *(s->top - 1);
    return -1;
}