std::max_element and overload operator()

[mickey]

Hello,
I need to do this but it, but with the //trick it works only with max_element. Do I have to write another class Less_Than ?
( I added that trick because it didn't work proper when NaN is the FIRST element of vector)

#include <limits>
class More_Than {
public:
	More_Than() {}
	bool operator() (const double& left, const double& right) {		
		if ( _isnan(left) ) return true; //trick
		if (left < right) 
			return true;
		return false;		
	}
};
int main (int argc, char** argv) {
 
	vector<double> vecInt(6);
	vecInt[0] = std::numeric_limits<double>::quiet_NaN();
	vecInt[1] = 9;
	vecInt[2] = 25;
	vecInt[3] = 50;
	vecInt[4] = 5;
	vecInt[5] = 33;
 
	double max = *std::max_element( vecInt.begin(), vecInt.end(), More_Than() );
	double min = *std::min_element( vecInt.begin(), vecInt.end(), More_Than() );
}

#include <limits>
class More_Than {
public:
	More_Than() {}
	bool operator() (const double& left, const double& right) {		
		if ( _isnan(left) ) return true; //trick
		if (left < right) 
			return true;
		return false;		
	}
};
int main (int argc, char** argv) {

	vector<double> vecInt(6);
	vecInt[0] = std::numeric_limits<double>::quiet_NaN();
	vecInt[1] = 9;
	vecInt[2] = 25;
	vecInt[3] = 50;
	vecInt[4] = 5;
	vecInt[5] = 33;

	double max = *std::max_element( vecInt.begin(), vecInt.end(), More_Than() );
	double min = *std::min_element( vecInt.begin(), vecInt.end(), More_Than() );
}

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[bood]

You can add a parameter to the More_Than class:

class More_Than {
    bool flag;
public:
    More_Than(bool f) {flag=f}
    bool operator() (const double& left, const double& right) {  
        if ( _isnan(left) ) return flag; //trick
        if (left < right)
            return true;
        return false;      
    }
};

class More_Than {
    bool flag;
public:
    More_Than(bool f) {flag=f}
    bool operator() (const double& left, const double& right) {  
        if ( _isnan(left) ) return flag; //trick
        if (left < right)
            return true;
        return false;      
    }
};

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However, I suggest kick those NaN numbers out of the list at the first place before you compare them.

[mickey]

there are many NaN to kick out, then it could be not fast....