daten2.h ----------------------------------------------------------------------------------------------------------
#include <iostream>
using namespace std;
#ifndef DATEN2_H_
#define DATEN2_H_

class Daten{
	private:
		int iwert;
	public:
		Daten(int iVal):iwert(iVal){
			cout << "Objekt [Daten] erzeugt\n";
		}
		~Daten(){}
		int vergleichen(const Daten&);
		void anzeigen() const;
		int get_iwert() const { return iwert; }
		friend bool operator <(const Daten& Dobj1, const Daten& Dobj2){
			if(Dobj1.iwert < Dobj2.iwert)
			{
				return true;
			}else{
				return false;
			}
		}
		friend bool operator ==(const Daten& Dobj1, const Daten& Dobj2){
			if(Dobj1.iwert == Dobj2.iwert){
				return true;
			}else{
				return false;
			}
		}
};

int Daten::vergleichen(const Daten& d){
	if(iwert > d.iwert){ 
		return 1; 
	}else if(iwert < d.iwert){
		return -1;
	}
	return 0;
}

void Daten::anzeigen() const{
	cout << iwert << '\n' << endl;
}
#endif
daten2.h END ----------------------------------------------------------------------------------------------------
temp.h ----------------------------------------------------------------------------------------------------------
#include <iostream>
#include <cstring>
using namespace std;
#ifndef TEMP_H_
#define TEMP_H_

class Temperatur{
	private:
		int grad;
		char monat[20];
	public:
		Temperatur(int iVal, char* m=""):grad(iVal)
		{
			strncpy(monat, m, 20);
			cout << "Objekt [Temperatur] erzeugt\n";
		}
		~Temperatur(){}
		int vergleichen(const Temperatur&);
		void anzeigen() const;
		friend bool operator <(const Temperatur& Tobj1, const Temperatur& Tobj2){
			if(Tobj1.grad < Tobj2.grad)
			{
				return true;
			}else{
				return false;
			}
		}
		friend bool operator ==(const Temperatur& Tobj1, const Temperatur& Tobj2){
			return(!(strcmp(Tobj1.monat, Tobj2.monat)));
		}
};

int Temperatur::vergleichen(const Temperatur& d){
	if(grad > d.grad){
		return 1;
	}else if(grad < d.grad){
		return -1;
	}
	return 0;
}

void Temperatur::anzeigen() const{
	cout << monat << " : " << grad << '\n';
}
#endif
temp2.h END -----------------------------------------------------------------------------------------------------
main.cpp --------------------------------------------------------------------------------------------------------
#include <iostream>
using namespace std;
#ifndef DATEN2_H_
#define DATEN2_H_

class Daten{
	private:
		int iwert;
	public:
		Daten(int iVal):iwert(iVal){
			cout << "Objekt [Daten] erzeugt\n";
		}
		~Daten(){}
		int vergleichen(const Daten&);
		void anzeigen() const;
		int get_iwert() const { return iwert; }
		friend bool operator <(const Daten& Dobj1, const Daten& Dobj2){
			if(Dobj1.iwert < Dobj2.iwert)
			{
				return true;
			}else{
				return false;
			}
		}
		friend bool operator ==(const Daten& Dobj1, const Daten& Dobj2){
			if(Dobj1.iwert == Dobj2.iwert){
				return true;
			}else{
				return false;
			}
		}
};

int Daten::vergleichen(const Daten& d){
	if(iwert > d.iwert){ 
		return 1; 
	}else if(iwert < d.iwert){
		return -1;
	}
	return 0;
}

void Daten::anzeigen() const{
	cout << iwert << '\n' << endl;
}
#endif
main.cpp END -----------------------------------------------------------------------------------------------------------------