FDS (LV) Ass 4 - Stack Ops

#include <iostream>
using namespace std;

class Stack {
    int stackSize;
    int stack[stackSize];
    int tos;
public:
    Stack(int sz) {
        tos = 0;
        stackSize = sz;
        stack[sz] = {0};
    }

    void push(int n){
        if (tos < stackSize){
            if (tos == stackSize - 1) {
                stack[tos] = n;
            } else {
                stack[tos] = n;
                tos++;
            }
        } else if (tos > stackSize - 1) {
            cout << "STACK OVERFLOW! CANNOT PUSH\n";
            tos = stackSize - 1;
        }
    }

    void pop(){
        int data = 0;
        if (tos == -1){
            cout << "STACK UNDERFLOW! CANNOT POP\n";
            tos = 0;
        } else if (tos == 0) {
            data = stack[0];
            cout << "Data: " << data << " has been popped\n";
        } else {
            data = stack[tos];
            cout << "Data: " << data << "has been popped\n";
            tos--;
        }
    }

    void display(){
        for (int i = tos - 1; i >= 0; i--){
            cout << stack[tos] << endl;
        }
    }
};


int main(){
    Stack ds(5);
    ds.push(1); //tos = 0
    ds.push(2); // 1
    ds.push(3);
    ds.push(4);
    ds.push(5);
    ds.display();
}