insert a template class issue

[gkrm123]

hello developers, I have a problem. I'have a library about RedBackTree.h. It is a template class and I'm creating a series from that class (RedBlackTree<Employee> Employes) then I create a class called Empoyee in my main file and insert it into this array but ı getting this error.

  required from here
RedBlackTree.h:97:23: error: no match for 'operator==' (operand types are 'Employee' and 'Employee')
   if(root->GetValue() == value)
In file included from C:/Program Files/mingw-w64/x86_64-8.1.0-posix-seh-rt_v6-rev0/mingw64/lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++/iosfwd:40,
                 from C:/Program Files/mingw-w64/x86_64-8.1.0-posix-seh-rt_v6-rev0/mingw64/lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++/ios:38,
                 from C:/Program Files/mingw-w64/x86_64-8.1.0-posix-seh-rt_v6-rev0/mingw64/lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++/ostream:38,
                 from C:/Program Files/mingw-w64/x86_64-8.1.0-posix-seh-rt_v6-rev0/mingw64/lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++/iostream:39,
                 from GorkemTuneri17244710055.cpp:1:
C:/Program Files/mingw-w64/x86_64-8.1.0-posix-seh-rt_v6-rev0/mingw64/lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++/bits/postypes.h:216:5: note: candidate: 'template<class _StateT> bool std::operator==(const std::fpos<_StateT>&, const std::fpos<_StateT>&)'
     operator==(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)

Where could I have done wrong? I'm showing header and main file

header

using namespace std;

template <class T> 
class RBNode
{
private:
	bool isRed;
	T value;
	RBNode<T> *left, *right, *parent;
public:
	RBNode(T value)
	{
		this->isRed = true;
		this->value = value;
		left = NULL;
		right = NULL;
		parent = NULL;
	}
	void Recolor()
	{
		if (this->isRed) this->isRed = false;
		else this->isRed = true;
	}
	bool IsRed()
	{
		return isRed;
	}
	T GetValue()
	{
		return this->value;
	}
	RBNode* GetLeft()
	{
		return this->left;
	}
	RBNode* GetRight()
	{
		return this->right;
	}
	RBNode* GetParent()
	{
		return this->parent;
	}
	void ClearParent()
	{
		this->parent = NULL;
	}
	void SetLeft(RBNode* left)
	{
		this->left = left;
		if(left != NULL) left->parent = this;
	}
	void SetRight(RBNode* right)
	{
		this->right = right;
		if(right != NULL) right->parent = this;
	}
};

template <class T> class RedBlackTree
{
private:
	RBNode<T>* root;

	RBNode<T>* AccessNode(RBNode<T> *root, T value)
	{
		if(root->GetValue() == value) 
		{
			return root;
		}
		else if(root->GetValue() > value)
		{
			if(root->GetLeft() == NULL)
			{
				return NULL;
			}
			else
			{
				return this->AccessNode(root->GetLeft(), value);
			}
		}
		else
		{
			if(root->GetRight() == NULL)
			{
				return NULL;
			}
			else
			{
				return this->AccessNode(root->GetRight(), value);
			}
		}
	}
	void InsertNode(RBNode<T> *root, T value)
	{
		RBNode<T>* insertedNode = NULL;
		if(root->GetValue() == value)
		{
			//skip
		}
		else if(root->GetValue() > value)
		{
			if(root->GetLeft() == NULL)
			{
				insertedNode = new RBNode<T>(value);
				root->SetLeft(insertedNode);
			}
			else
			{
				this->InsertNode(root->GetLeft(), value);
			}
		}
		else
		{
			if(root->GetRight() == NULL)
			{
				insertedNode = new RBNode<T>(value);
				root->SetRight(insertedNode);
			}
			else
			{
				this->InsertNode(root->GetRight(), value);
			}
		}
		if (insertedNode == NULL) return;
		this->SolveDoubleRedProblem(root);
		insertedNode = NULL;
	}
	
	void SolveDoubleRedProblem(RBNode<T> *root)
	{
		if (root->IsRed() == false) return;
		if (root == root->GetParent()->GetLeft())
		{
			if (root->GetParent()->GetRight() == NULL || !root->GetParent()->GetRight()->IsRed()) this->RightRotate(root);
			else
			{
				root->Recolor();
				root->GetParent()->GetRight()->Recolor();
				root->GetParent()->Recolor();
				if (root->GetParent()->GetParent() == NULL)
				{
					root->GetParent()->Recolor();
					return;
				}
				SolveDoubleRedProblem(root->GetParent()->GetParent());
			}
		}
		else
		{
			if (root->GetParent()->GetLeft() == NULL || !root->GetParent()->GetLeft()->IsRed()) this->LeftRotate(root);
			else
			{
				root->Recolor();
				root->GetParent()->GetLeft()->Recolor();
				root->GetParent()->Recolor();
				if (root->GetParent()->GetParent() == NULL)
				{
					root->GetParent()->Recolor();
					return;
				}
				SolveDoubleRedProblem(root->GetParent()->GetParent());
			}
		}
	}
	void LeftRotate(RBNode<T> *root)
	{
		RBNode<T> *parent = root->GetParent();
		if (root->GetLeft() != NULL && root->GetLeft()->IsRed())
		{
			RBNode<T> *badChild = root->GetLeft();
			root->SetLeft(badChild->GetRight());
			badChild->SetRight(root);
			parent->SetRight(badChild);
			root = badChild;
		}
		root->Recolor();
		parent->Recolor();
		parent->SetRight(root->GetLeft());
		if (parent->GetParent() != NULL)
		{
			if (parent->GetParent()->GetLeft() == parent) parent->GetParent()->SetLeft(root);
			else parent->GetParent()->SetRight(root);
		}
		else
		{
			this->root = root;
			this->root->ClearParent();
			root = this->root;
		}
		root->SetLeft(parent);
	}
	void RightRotate(RBNode<T> *root)
	{
		RBNode<T> *parent = root->GetParent();
		if (root->GetRight() != NULL && root->GetRight()->IsRed())
		{
			RBNode<T> *badChild = root->GetRight();
			root->SetRight(badChild->GetLeft());
			badChild->SetLeft(root);
			parent->SetLeft(badChild);
			root = badChild;
		}
		root->Recolor();
		parent->Recolor();
		parent->SetLeft(root->GetRight());
		if (parent->GetParent() != NULL)
		{
			if (parent->GetParent()->GetLeft() == parent) parent->GetParent()->SetLeft(root);
			else parent->GetParent()->SetRight(root);
		}
		else
		{
			this->root = root;
			this->root->ClearParent();
			root = this->root;
		}
		root->SetRight(parent);
	}
	

public:
	RedBlackTree()
	{
		this->root = NULL;
	}
	bool IsEmpty()
	{
		return root == NULL;
	}
	RBNode<T>* AccessNode(T value)
	{
		if (this->IsEmpty()) return NULL;
		else return this->AccessNode(root, value);
	}
	void InsertNode(T value)
	{
		if (this->IsEmpty())
		{
			this->root = new RBNode<T>(value);
			this->root->Recolor();
		}
		else this->InsertNode(this->root, value);
	}

};

[coder777]

The problem is that you compare the values of the RedBlackTree (Line 67/97) but the class Employee does not have an operator==(). So the compiler does not know how to do that.

The operator>() does not exist either.

You need something like this:

class Employee
{
public:
  int IdNumber;
  int ID2;
  int phoneNumber;
  void setIDnubmer(int Name);
  void setPhone(int Name);
  void setID2(int Name);
  Employee();

  bool operator==(const Employee& that) const
  {
    return (IdNumber == that.IdNumber) && (ID2 == that.ID2) && ...; // Whatever is needed for the comparison
  }

  bool operator!=(const Employee& that) const
  {
    return !operator==(that);
  }
};

The other needed operators are similar.

[seeplus]

As it says in the error message, you need to provide an operator== overload for the Employee class. You also need an operator>.

Something like:

class Employee
{
public:
	int IdNumber;
	int ID2;
	int phoneNumber;
	void setIDnubmer(int Name);
	void setPhone(int Name);
	void setID2(int Name);
	Employee();
	bool operator==(const Employee& rhs) const { return IdNumber == rhs.IdNumber; }
	bool operator>(const Employee& rhs) const { return IdNumber < rhs.IdNumber; }
};

This causes the code to compile with no errors (VS2019 - just warnings).

[gkrm123]

thank youu. I have to one question. So, How can I search Employee by IdNumber from Students list using RedBLackTree library?

[seeplus]

If the code in the first post is from a library, it is outdated and not good code for modern C++.

To find a node with a particular value, then you use AccessNode() which either returns nullptr if not found or a pointer to the node with the required value.

So simply (not tried):

if (const auto ndptr (students.AccessNode(e)}; ndptr != nullptr)
    std::cout << "found " << ndptr->value.Idnumber << "  " << ndptr->value.Id2 << '\n';
else
    std::cout << "Not found\n";

[gkrm123]

you saved my life thank you