QDebug operator << (QDebug dbg, const Histogram &histogram) { dbg.nospace() << "["; for (int i = histogram.min(); i <= histogram.max(); ++i) { if (histogram.at(i) > 0) { dbg.nospace() << i << "=" << histogram.at(i); if (i <= histogram.max() - 1) dbg.nospace() << " "; } } dbg.nospace() << "]"; return dbg.space(); }