// program to convert decimal to OCTAL
#include 
using namespace std;

#define size 50

int st[size];
int top = -1;

void push(int);
int pop();
int isempty();
int isfull();

int main()
{
    int num, n, r;
    cout << "\nenter decimal number: ";
    cin >> num;

    n = num;
    while (n >= 1)
    {
        r = n % 8;
        push(r);
        n = n / 8;
    }

    cout << "DECIMAL :: " << num << endl;
    cout << "OCTAL   :: ";

    while (!isempty())
        cout << pop();

    return 0;
}

int isempty()
{
    if (top == -1)
        return 1;

    return 0;
}

int isfull()
{
    if (top == size - 1)
        return 1;

    return 0;
}

void push(int r)
{
    if (isfull())
        cout << ("\nSTACK OVERFLOW\n");
    else
        st[++top] = r;
}

int pop()
{
    if (isempty())
    {
        return 0;
        cout << ("\nSTACK UNDERFLOW\n");
    }
    else
        return st[top--];
}