Russian Qt Forum

C++ (Qt)
template <class T>
int GetMaxNegative( const T & vec )
{
	int maxV = 0;
	for (size_t i = 0; i < vec.size(); ++i) {
		int val = vec[i];
		if (val >= 0) continue;
		if (!maxV || val > maxV)
			maxV = val;
	}
 
	return maxV;
}

C++ (Qt)
int GetMaxNegative( const QWidgetList & vec )
{
	int maxV = 0;
	for (size_t i = 0; i < vec.size(); ++i) {
		int val = vec[i]->x();
		if (val >= 0) continue;
		if (!maxV || val > maxV)
			maxV = val;
	}
 
	return maxV;
}

C++ (Qt)
#include <vector>
#include <iostream>
 
using namespace std;
 
template<typename Ret, typename It, typename Func>
Ret getMaxNegative( It beg, It end, Func get )
{
	Ret maxV = 0;
	for( It i = beg; i != end; ++i )
	{
		Ret val = get( *i );
		if( val >= 0 )
			continue;
 
		if( !maxV || val > maxV )
			maxV = val;
	}
 
	return maxV;
}
 
template<typename Ret, typename It>
Ret getMaxNegative( It beg, It end )
{
	return getMaxNegative<Ret, It>( beg, end, []( Ret v ) { return v; } );
}
 
struct Point
{
	int		x;
	int		y;
};
 
int main( int, char ** )
{
	cout << "Hello World!" << endl;
 
	std::vector<int> v{ 3, -1, -14, 1, 5, 9 };
	cout << "Result = " << getMaxNegative<int>( v.begin(), v.end() ) << endl;
 
	std::vector<Point> p{ { 10, 10 }, { 20, 20 }, { -30, 30 }, { -10, 40 } };
	cout << "Result = " << getMaxNegative<double>( p.begin(), p.end(), []( const Point &v ){ return v.x; } ) << endl;
 
	return 0;
}
 

C++ (Qt)
template <class T>
int GetVectorValue(const T & vec, int index) const
{
    return vec[index];
}
 
template <class T>
int GetVectorValueByX(const T & vec, int index) const
{
    return vec[index]->x();
}
 
template <class T>
int GetVectorValueByY(const T & vec, int index) const
{
    return vec[index]->y();
}
 
// ... blabla
 
template <class T, class F = GetVectorValue>
int GetMaxNegative( const T & vec, F* fvec  )
{
	int maxV = 0;
	for (size_t i = 0; i < vec.size(); ++i) {
		int val = fvec(vec, i);
		if (val >= 0) continue;
		if (!maxV || val > maxV)
			maxV = val;
	}
 
	return maxV;
}
 

C++ (Qt)
template <class>
struct getter_helper
{
    template <class R, class U>
    static R get(const U & x)
    {
        return x;
    }
};
 
template <>
struct getter_helper<QPoint>
{
    template <class R, class U>
    static R get(const U & p)
    {
        return p.x();
    }
};
 
template <class T>
int GetMaxNegative( const T & vec)
{
    int maxV = 0;
    for (size_t i = 0; i < vec.size(); ++i) {
        int val = getter_helper<typename T::value_type>::get(vec[i]);
        if (val >= 0) continue;
        if (!maxV || val > maxV)
            maxV = val;
    }
 
    return maxV;
}
 

C++ (Qt)
struct CWxContainer {
 CWxContainer( const QWdgetList & lst, QWidget * coord ) :
   mLst(lst),
   mCoord(coord)
  {
  }
 
  size_t size( void ) const { return mLst.size(); }
  int operator[] ( size_t index ) const { return mCoord->mapFromGlobal(mLst[index]->mapToGlobal(QPoint(0, 0))).x(); }
 
// data
 const QWdgetList & mLst;
 QWidget * mCoord;
};

C++ (Qt)
getMaxNegative<double>( p.begin(), p.end(), []( const Point &v ){ return v.x; } )

C++ (Qt)
getMinPositive<double>( p.begin(), p.end(), []( const Point &v ){ return v.x; } )

C++ (Qt)
template <class T>
int GetVectorValue(const T & vec, int index) const
{
    return vec[index];
}
 
...