remove 4 element

4_element.cpp

#include<iostream>
#include<array>

using namespace std;


// Stack Container to simplify Stack
// operations 
template<typename T,int SIZE>
struct Stack{
//     array<T, SIZE> elements;
    T elements[SIZE];
    int &operator[](int i) {
        if(top > -1)
            return elements[i];
    }

    void push(T el){
        if(top >= SIZE){
            cout << "STACK IS FULL" << endl;
        }else{
            elements[++top] = el;
        }
    }

    int pop(void){
        if(top <= -1){
            cout << "STACK is empty" << endl;
        }else{
            return elements[top--];
        }
    }

    void show(void){
        if(top >= 0){
            cout << "The elements of STACK is ......" << endl;
            for(int i=top; i >= 0; i--)
                cout << "The Element : " << elements[i] << endl;
        }
    }

private:
    int top = -1;
};
int main(void){
    Stack<int, 4> s1;
    Stack<int, 4> s2;
    Stack<int, 4> s3;

    s1.push(4);
    s1.push(3);
    s1.push(2);
    s1.push(1);

    cout << "STACK 1" << endl;
    s1.show();

    // we moved 1 to s2 and 2 to s3
    s2.push(s1.pop());
    s3.push(s1.pop());

    // show the stack 1
    cout << "STACK 1" << endl;
    s1.show();

    // we moved 1 to s3 top of 2 because it's smaller than it
    // and s2 now is empty
    s3.push(s2.pop());
    cout << "STACK 3" << endl;
    s3.show();

    // we moved 3 to s2
    s2.push(s1.pop());
    // show the stack 1
    cout << "STACK 1" << endl;
    s1.show();

    // now we delete 4 from s1
    cout << "POP UP THE " << s1.pop() << " FROM STACK 1" << endl;
    // let's move the 1, 2, and 3 to s1
    s1.push(s2.pop());
    s2.push(s3.pop());
    s1.push(s3.pop());
    s1.push(s2.pop());

    // show the stack 1
    cout << "STACK 1" << endl;
    s1.show();
    return 0;
}