#include<iostream>
 
using namespace std;
 
struct Calculator
{
    enum eSAFETY{ eMAXIMUM, eMINIMUM };
 
    void Work()const
    {
        cout << ((mSafety==eMAXIMUM)? "max_level": "min_level")<<endl;
    }
 
    eSAFETY mSafety;
};
 
 
int main()
{
   Calculator obj;
   obj.mSafety = Calculator::eMAXIMUM;
   obj.Work();

   //попытка подсунуть что-то некорректное
   //obj.mSafety = 10;

   //error: invalid conversion from 'int' to 'Calculator::eSAFETY'

   return 0;
}

max_level