#include
using namespace std;
class StackElem {
public:
int data;
StackElem* next_elem;
StackElem() {
next_elem = nullptr;
}
StackElem(int value) {
data = value;
next_elem = nullptr;
}
};
class Stack
{
static const int SUCCESS = 0;
static const int ERR_EMPTY = 1;
private:
StackElem* top;
public:
Stack() {top = nullptr;}
bool isEmpty() {
return top == nullptr;
}
int pop() {
if (isEmpty()) {
return ERR_EMPTY;
}
StackElem* tmp = top;
int ret = tmp->data;
top = top->next_elem;
delete tmp;
return ret;
}
void push(int data) {
StackElem* elem = new StackElem(data);
elem->next_elem = top;
top = elem;
}
int peek() {
if (isEmpty()) {
return ERR_EMPTY;
}
return top->data;
}
void printStack() {
if (isEmpty()) {
printf("Stack is empty.\n");
return;
}
printf("Current Stack:\n");
StackElem* elem = top;
while (elem != nullptr) {
printf("%d\n", elem->data);
elem = elem->next_elem;
}
}
};
int main() {
Stack* s = new Stack();
s->printStack();
printf("push(3)\n");
s->push(3);
printf("push(1)\n");
s->push(1);
printf("push(100)\n");
s->push(100);
s->printStack();
printf("pop(): %d\n", s->pop());
printf("pop(): %d\n", s->pop());
printf("pop(): %d\n", s->pop());
s->printStack();
return 0;
}