Stack

#include <iostream>
using namespace std;
template <class T>
class Stack {
private:
	T * data;
	int size;
	int head;
public:
	Stack(int _s) : size(_s) {
		if ((data = (T*)malloc(sizeof(T)*size)) == NULL) {
			fprintf(stderr, "MALLOC ERROR\n");
		}
		head = 0;
	}
	Stack() {
		size = 10;
		if ((data = (T*)malloc(sizeof(T)*size)) == NULL) {
			fprintf(stderr, "MALLOC ERROR\n");
		}
		head = 0;
	}
	void push(T d) {
		if (head<size) { data[head++] = d; return; }
		else {
			size *= 2;
			if ((data = (T*)realloc(data, sizeof(T)*size)) == NULL) {
				fprintf(stderr, "REALLOC ERROR\n");
				return;
			}
			data[head++] = d;
			return;
		}
	}
	void pop() { head--; }
	T top() { return data[head - 1]; }
};
int main(int argc, char** argv) {
	Stack<int> s;
	for (int i = 0; i<13; i++)
		s.push(i);
	for (int i = 0; i<13; i++) {
		cout << s.top() << endl;
		s.pop();
	}
	return 0;
}