struct Node{
int num;
struct Node *prox;
};
typedef struct Node node;

int tam;

int vazia(node *LISTA)
{
if(LISTA->prox == NULL)
    return 1;
else
    return 0;
}

node *aloca()
{
node *novo=(node *) malloc(sizeof(node));
if(!novo){
    printf("Sem memoria disponivel!n");
    exit(1);
}else{
    printf("Novo elemento: ");
    scanf("%d", &novo->num);
    return novo;
}
}