Bit Flags Issue

After finishing reading a tutorial on bit flags, i decided to do some practicing.

Here's what I came up with:

Code:

---

#include <iostream>
#include <string>

using namespace std;

enum PersonSettings
{
    Works = 1,
    Studies = 2,
    HasKids = 4,
    LivesAlone = 8
};

class Person
{
    public:
        Person(string n, PersonSettings s);
        void printSettings();
    private:
        string name;
        PersonSettings settings;
};

Person::Person(string n, PersonSettings s) : name(n), settings(s)
{

}

void Person::printSettings()
{
    cout<<"WORKS? ";
    if(settings & Works) cout<<"YES"; else cout<<"NO";
    cout<<endl;

    cout<<"STUDIES? ";
    if(settings & Studies) cout<<"YES"; else cout<<"NO";
    cout<<endl;

    cout<<"HAS KIDS? ";
    if(settings & HasKids) cout<<"YES"; else cout<<"NO";
    cout<<endl;

    cout<<"LIVES ALONE? ";
    if(settings & LivesAlone) cout<<"YES"; else cout<<"NO";
    cout<<endl;
}

int main()
{
    Person someone("Jack",LivesAlone | HasKids);
    someone.printSettings();
    cout<<endl;
}

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It works well ONLY if set one bit flag on the constructor, if i try to set more than one bit flag (like in the code above) it displays the following error report:

Quote:

---

error: invalid conversion from `int' to `PersonSettings'|

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line of error:

Quote:

---

Person someone("Jack",LivesAlone | HasKids);

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Oh, and BTW, is this a correct usage of bit flags?

Well the combined result isn't a valid enum value.

An enum is a rather more distinct type in C++ than it is in C.
Incompatibilities Between ISO C and ISO C++

still, it's not clear to me why the OR bit operator doesnt work as it should.

I'll even write a simpler code that makes the compiler reports the same error message:

Code:

---

#include <iostream>
#include <stdlib.h>

int main()
{

      enum mySettings
      {
          opt1 = 1,
          opt2 = 2,
          opt3 = 4,
          opt4 = 8
      };

      mySettings options;
      options = opt3 | opt4;

      cout<<hex<<options<<endl;

      system("PAUSE");
      return 0;
}

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Quote:

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Originally Posted by dhuan

still, it's not clear to me why the OR bit operator doesnt work as it should.

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As already indicated by Salem, the OR is executed correctly, the result is simply not a valid enum value, so that you cannot assign the result., hence the error. In your example, 4 | 8 = 12. There is no enum member with a value of 12, hence the compiler bails.