Stack.h

#define MAX 10
#define ERRORSTACKEMPTY -2
#define ERRORSTACKFULL -1

typedef struct{
	int item[MAX];
	int top;
}Stack;

int push(Stack *p,int x);
int pop(Stack *p);
void iniStack(Stack *p);
int stackIsEmpty(Stack *p);
int stackIsFull(Stack *p);
void listStack(Stack *p);

void listStack(Stack *p){
	int i;
		if (stackIsEmpty(p)==ERRORstackIsEmpty) 
			printf ("The stack cannot be displayed because is empty!\n");
		else{
			printf ("Stack elements in order:\n");
			for (i=p->top-1;i>-1;i--){
				printf ("%d\n",p->item[i]);
			}
		}
}
int push(Stack *p,int x){
	if ((stackIsFull(p))==1)
		return (ERRORSTACKFULL); // Erro
	else{
			p->item[p->top]=x;
			p->top++;
			return (p->top);
		}
}
int pop(Stack *p){
	if ((stackIsEmpty(p))==1)
		return (ERRORstackIsEmpty); // Erro
	else{
		p->top--;
		return(p->item[p->top]);
	}
}
void iniStack(Stack *p){
	p->top=0;
}
int stackIsEmpty(Stack *p){
	if (p->top==0)
		return ERRORstackIsEmpty;
	else
		return 0;
}
int stackIsFull(Stack *p){
	if (p->top==MAX)
		return ERRORstackIsFull;
	else
		return 0;
}