intro_to_stack.cpp

#include<bits/stdc++.h>
using namespace std;

#define n 100

class Stack {
    int* arr;
    int top;

    public:
        Stack() {
            arr = new int[n];
            top = -1;
        }

        void push(int x) {
            if(top == n-1) {
                cout<<"Stack overflow"<<endl;
                return;
            }

            top++;
            arr[top] = x;
        }

        void pop() {
            if(top == -1) {
                cout<<"Stack is empty"<<endl;
                return;
            }
            
            top--;
        }

        int getTop() {
            if(top == -1) {
                cout<<"Stack is empty"<<endl;
                return -1;
            }

            return arr[top];
        }

        bool isEmpty() {
            return top==-1;
        }
};

int main() {

    Stack st;
    st.push(1);
    st.push(2);
    st.push(3);
    cout<<st.getTop()<<endl;
    
    st.pop();
    cout<<st.getTop()<<endl;

    st.pop();
    st.pop();
    st.pop();

    cout<<st.isEmpty()<<endl;
    cout<<st.getTop()<<endl;

    return 0;
}