Стек на массиве

#include <iostream>

class Stack
{
private:
    int size;
    float* array;
public:
    Stack();
    ~Stack();

    void push_back(float value);
    void pop_back();
    bool is_empty() { return !size; };
    float top_value() { if (size > 0) { return array[size - 1]; } else { std::cout << "Error. The stack is empty." << std::endl; return 0; } };
    void print_stack();

};
Stack::Stack() {
    array = new float[0];
    size = 0;
}

Stack::~Stack() {
    while (size) {
        pop_back();
    }
}

void Stack::push_back(float value) {
    size++;
    float* tmp = new float[size];
    for (int i = 0; i < size - 1; i++) {
        tmp[i] = array[i];
    }
    tmp[size - 1] = value;
    delete[] array;
    array = tmp;
}

void Stack::pop_back() {
    if (size > 0) {
        size--;
        float* tmp = new float[size];
        for (int i = 0; i < size; i++) {
            tmp[i] = array[i];
        }
        delete[] array;
        array = tmp;
    }
}
void Stack::print_stack() {
    for (int i = 0; i < size; i++) {
        std::cout << array[i] << " ";
    }
    std::cout << std::endl;
}

int main()
{
    Stack st;
    st.push_back(1);
    st.push_back(2);
    st.push_back(3);
    std::cout << st.top_value() << std::endl;
    st.pop_back();
    st.print_stack();
    std::cout << st.is_empty() << std::endl;
    st.pop_back();
    st.pop_back();
    std::cout << st.is_empty() << std::endl;
    st.pop_back();
    std::cout << st.top_value() << std::endl;
    return 0;
}