Untitled

#include <iostream>

using namespace std;

int main()
{
    double side;
    double volume;

    cout << "Podaj dlugosc boku szescianu: ";

    while (!(cin >> side) || side <= 0)
    {
        cin.clear();
        cin.ignore(numeric_limits<streamsize>::max(), '\n');
        cout << "Prosze podac liczbe dodatnia: ";
    }

    volume = side * side * side;

    cout << "Objetosc szescianu wynosi " << volume << endl;

    return 0;
}