Re: Custom iterator or custom predicate?
Kenneth Porter wrote:
I went with a custom predicate:
// compares two vectors on the nth element
template <class V, unsigned index>
class VectorElementLess : std::less<V>
{
public:
bool operator()(const V& _Left, const V& _Right) const
{
return std::less<V::value_type>()(_Left[index], _Right[index]);
Is there any magic using std::less<> here?
why not just "return _Left[index] < _Right[index];" ?
name starting with underscore followed by a capital letter is
reserved for implementation usage.
}
};
why inherit from std::less? which introduces a hiding of operator() in
std::less
maybe std::binary_function<V, V, bool> is better.
typedef std::vector<std::vector<int> > Array2D;
Array2D samples; // passed in parameter, known to be non-empty
const unsigned sensorIndex = 1;
typedef VectorElementLess<Array2D::value_type, sensorIndex> SensorLess;
// find the sample with the maximum sensor reading
std::vector<int> maxSensor = *std::max_element(samples.begin(), samples.end
(), SensorLess());
maybe keep using an iterator as the index found is better
--
Best Regards
Barry
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