a question in NS c++ programming

I added a new patch to my NS and I've seen these two errors. Does anyone know what I can do?

error: specialization of 'bool std::less<_Tp>::operator()(const _Tp&, const _Tp&) const [with _Tp = _AlgorithmTime]' in different namespace
from definition of 'bool std::less<_Tp>::operator()(const _Tp&, const _Tp&) const [with _Tp = _AlgorithmTime]'

and the errors are from this code

typedef struct _AlgorithmTime {
    // Round.
    int             round;
    // Fase.
    int             fase;
    // Valore massimo di fase.
    int             last_fase;

    public:

        _AlgorithmTime() {
            round = 0;
            fase = 0;
            last_fase = 0;
        }

        // Costruttore.
        _AlgorithmTime(int r, int f, int l) {
            round = r;
            fase = f;
            last_fase = l;
        }

        // Costruttore.
        _AlgorithmTime(const _AlgorithmTime & t) {
            round = t.round;
            fase = t.fase;
            last_fase = t.last_fase;
        }

        // Operatore di uguaglianza.
    开发者_如何学编程    bool operator== (struct _AlgorithmTime & t) {
            return ((t.fase == fase) && (t.round == round));
        }

        // Operatore minore.
        bool operator < (struct _AlgorithmTime & t) {
            if (round < t.round)
                return true;
            if (round > t.round)
                return false;
            if (fase < t.fase)
                return true;
            return false;
        }

        // Operatore maggiore.
        bool operator > (struct _AlgorithmTime & t) {
            if (round > t.round)
                return true;
            if (round < t.round)
                return false;
            if (fase > t.fase)
                return true;
            return false;
        }

        void operator++ () {
            if (fase == last_fase) {
                round++;
                fase = 0;
                return;
            }
            fase++;
        }

        void operator-- () {
            if (fase == 0) {
                round--;
                fase = last_fase;
                return;
            }
            fase--;
        }
}AlgorithmTime;

template<>
bool
std::less<AlgorithmTime>::operator()(const AlgorithmTime & t1, const AlgorithmTime & t2)const
{
    if (t1.round < t2.round)
        return true;
    if (t1.round > t2.round)
        return false;
    if (t1.fase < t2.fase)
        return true;
    return false;
}

Thanks

If your specialization of std::less<AlgorithmTime>::operator() is inside your namespace, that's probably what the compiler is complaining about - you'd need to have the specialization at the 'global' namespace level.

As an aside, while it's fine to specialize std::less, there's no need to in your case - the standard definition of std::less<AlgorithmTime> will use the AlgorithmTime::operator<() to do its work.

You could just specify the namespace of the template you are trying to specialize:

namespace std
{
  template<>
  bool
  std::less<AlgorithmTime>::operator()(const AlgorithmTime & t1, const AlgorithmTime & t2)const
  {
    ...
  }
}

But as Michael Burr points out, there's no reason to specialize std::less, if all you intend to do is duplicate the code of AlgorithmTime::<.

The problem is that you are creating a template specialization of std::less::operator() for the AlgorithmTime class, but this specialization is in a different namespace than the original template of the function.

You can fix this by explicitly declaring your specialization to be in the std namespace, like so:

namespace std{
    template<>
    bool
    less<AlgorithmTime>::operator()(const AlgorithmTime & t1, const AlgorithmTime & t2)const // "std::less" is no longer necessary
    {
        if (t1.round < t2.round)
            return true;
                if (t1.round > t2.round)
            return false;
        if (t1.fase < t2.fase)
            return true;
        return false;
    }
}