Error in map

[Shervan360]

Hello,

could you please help me?

Severity Code Description Project File Line Suppression State
Error C2676 binary '<': 'const _Ty' does not define this operator or a conversion to a type acceptable to the predefined operator C++_6 C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Tools\MSVC\14.28.29910\include\xstddef 127

  #include <iostream>
#include <vector>
#include <iterator>
#include <map>
using namespace std;

class Student
{
private:
	int SID;
	string name;
	string family;
	double mean;
public:
	Student(int id = 0, string _name = " ", string _family = " ", double _mean = 0)
	{
		SID = id;
		name = _name;
		family = _family;
		mean = _mean;
	}
	Student(const Student& s)
	{
		SID = s.SID;
		name = s.name;
		family = s.family;
		mean = s.mean;
	}
	void setSID(int id)
	{
		SID = id;
	}
	void setName(string _name)
	{
		name = _name;
	}
	void setFamily(string _family)
	{
		family = _family;
	}
	void setMean(double _mean)
	{
		mean = _mean;
	}
	int getSID()
	{
		return SID;
	}
	string getName()
	{
		return name;
	}
	string getFamily()
	{
		return family;
	}
	double getMean()
	{
		return mean;
	}

};

class Course
{
	int CID;
	string name;
	string profName;
	int numOfTAs;
	int numOfStudents;
	vector<Student> TAs;
	map<Student, int> studentGrades;
public:
	Course(vector<Student> _TAs, map<Student, int>  _studentGrades,
		int id = 0, string _name = "", string _profName = "",
		int _numOfTAs = 0, int _numOfStudents = 0)
	{
		CID = id;
		name = _name;
		profName = _profName;
		numOfTAs = _numOfTAs;
		numOfStudents = _numOfStudents;
		TAs = _TAs;
		studentGrades = _studentGrades;
	}
};

int main()
{
	//Student s1(10, "Dani", "Babak", 10);
	//Student s2(11, "Iran", "Irani", 10);
	//Student s3(12, "Ebi", "mahdi", 10);

	//vector<Student> Students;
	//Students.push_back(s1);
	//Students.push_back(s2);
	//Students.push_back(s3);

	map<Student, int> myStudentsGrades;

	Student s4(10, "TA04", "TA4", 4);
	Student s5(11, "TA05", "TA5", 5);
	Student s6(12, "TA06", "TA6", 6);

	//myStudentsGrades[s4] = 20;

	myStudentsGrades.insert(make_pair(s4, 20)); // ERROR
	//studentsGrades.insert(pair<Student, int>(s5, 19));
	//studentsGrades.insert(pair<Student, int>(s6, 18));
}

[lastchance]

If you use a Student as a key for a std::map, then you need to define an ordering relation (i.e. the operator < ) for a Student.

[Shervan360]

I solved the previous error but now I have another error:

Severity Code Description Project File Line Suppression State
Error (active) E0289 no instance of constructor "Course::Course" matches the argument list C++_6 C:\Users\My\source\repos\C++_6\C++_6\Source.cpp 134


Severity Code Description Project File Line Suppression State
Error C2664 'Course::Course(std::vector<Student,std::allocator<Student>>,std::map<Student,int,std::less<Student>,std::allocator<std::pair<const Student,int>>>,int,std::string,std::string,int,int)': cannot convert argument 1 from 'std::vector<Student,std::allocator<Student>> *' to 'std::vector<Student,std::allocator<Student>>' C++_6 C:\Users\My\source\repos\C++_6\C++_6\Source.cpp 122

#include <iostream>
#include <vector>
#include <iterator>
#include <map>
using namespace std;

class Student
{
private:
	int SID;
	string name;
	string family;
	double mean;
public:
	Student(int id = 0, string _name = " ", string _family = " ", double _mean = 0)
	{
		SID = id;
		name = _name;
		family = _family;
		mean = _mean;
	}
	Student(const Student& s)
	{
		SID = s.SID;
		name = s.name;
		family = s.family;
		mean = s.mean;
	}
	void setSID(int id)
	{
		SID = id;
	}
	void setName(string _name)
	{
		name = _name;
	}
	void setFamily(string _family)
	{
		family = _family;
	}
	void setMean(double _mean)
	{
		mean = _mean;
	}
	int getSID()
	{
		return SID;
	}
	string getName()
	{
		return name;
	}
	string getFamily()
	{
		return family;
	}
	double getMean()
	{
		return mean;
	}

};

class Course
{
	int CID;
	string name;
	string profName;
	int numOfTAs;
	int numOfStudents;
	vector<Student> TAs;
	map<Student, int> studentGrades;
public:
	Course(vector<Student> _TAs, map<Student, int>  _studentGrades,
		int id = 0, string _name = "", string _profName = "",
		int _numOfTAs = 0, int _numOfStudents = 0)
	{
		CID = id;
		name = _name;
		profName = _profName;
		numOfTAs = _numOfTAs;
		numOfStudents = _numOfStudents;
		TAs = _TAs;
		studentGrades = _studentGrades;
	}
	bool addTA(Student ta)
	{
		vector<Student>::iterator it;
		it = find(TAs.begin(), TAs.end(),ta);
		if (it != TAs.end())
		{
			TAs.push_back(ta);
			return true;
		}
		else
			return false;
	}
	bool addStudent(Student student)
	{
		map<Student, int>::iterator it;
		it = find(studentGrades.begin(), studentGrades.end(), student);
		if (it != studentGrades.end())
		{
			studentGrades.insert(make_pair(student, 0));
			return true;
		}
		else
			return false;
	}
};

int main()
{
	Student s1(10, "Dani", "Babak", 10);
	Student s2(11, "Iran", "Irani", 10);
	Student s3(12, "Ebi", "mahdi", 10);

	vector<Student> Students ;
	Students.push_back(s1);
	Students.push_back(s2);
	Students.push_back(s3);

	map<Student*, int> myStudentsGrades;

	Student* s4 = new Student(10, "TA04", "TA4", 4);
	Student* s5 = new Student(11, "TA05", "TA5", 5);
	Student* s6  = new Student(12, "TA06", "TA6", 6);


	myStudentsGrades.insert(make_pair(s4, 20)); 
	myStudentsGrades.insert(make_pair(s5, 19));
	myStudentsGrades.insert(make_pair(s6, 18));

	Course Math(Students, myStudentsGrades, 101, "Math", "mahdi", 3, 3); //ERROR
}