#include <iostream>
#include <stdexcept>

class Ranged_Integer
{
public:
    Ranged_Integer(int i)
        : value{i}
    {
        check(i);
    }
    
    int get() const
    {
        return value;
    }
    
    void set(int i)
    {
        check(i);
        value = i;
    }
  
private:

    void check(int i) const
    {
        if ( i < 15 || i > 35 )
        {
            throw std::logic_error{"Out of range [15,35]"};
        }
    }
  
    int value;
};

using namespace std;

int main()
{
    Ranged_Integer const i{20};

    cout << i.get() << endl;
  
    Ranged_Integer j{10};
}