i know how to get a file and all but how do u go about putting that file into the tree?

my get file

void BST::loadFile()
{
	cout << "Enter the the file location" << endl;
	cin >> inFileName;
	inFile.open(inFileName.c_str());
	if (!inFile.is_open())  //test for file
	{
		cerr << "Cannot open file: " << inFileName << endl;
		getche();
	}
	while(!inFile.eof()) //loop through untill end of file
	{ 
		inFile >> lastName >> firstName; 

		cout << lastName << ", " << firstName <<  endl; 
 
	}// end obtain info 

	inFile.close();//close infile
}

do i just go key = inFile
here is my key struct

struct Key {
	char* data;  // string

	Key();
	Key(char* data) { this->data = new char[strlen(data)];
								strcpy(this->data,data);}
	~Key() {delete data;};
	Key(Key& key);
	void print();

	Key& operator= (Key& key);
	bool operator== (Key& key) { return 0 == strcmp(this->data,key.data);} // is this == to that key
	bool operator< (Key& key)  { return -1 == strcmp(this->data,key.data);}// is this < that key
	bool operator> (Key& key)  { return 1 == strcmp(this->data,key.data);} // is this > that key
};


Key::Key()
{
	data = NULL;
}

Key::Key(Key& key)
{
	data = key.data;
}

Key& Key::operator= (Key& key)
{
	data = key.data;
	return *this;
}

void Key::print()
{
	cout << data << endl;
}

my BST Class

class BST_Node {
private:
	Key key;         // key holds the data
	BST_Node* left;  // ptr to left subtree
	BST_Node* right; // ptr to right subtree

public:
	// Managers
	BST_Node();
	BST_Node(Key key);        // Construct given key-data
	BST_Node(BST_Node& node); // Copy Constructor
	~BST_Node();              // Destruct node

	// Operators
	BST_Node& operator= (BST_Node& node); // Assignment

	// Accessors
	Key getKey() {return key;};         // get Key Data
	BST_Node* getLeft() {return left;};  // get root of left subtree
	BST_Node* getRight() {return right;}; // get root of right subtree
	void setLeft(BST_Node* node);
	void setRight(BST_Node* node);
};

BST_Node::BST_Node()
{
	key.data = NULL;
	left = NULL;
	right = NULL;
}

BST_Node::BST_Node(Key key)
{	
	
	cout << "enter key" << endl;
	cin >> key.data;

}

BST_Node::BST_Node(BST_Node& node)
{
	right = node.right;
	left = node.left;
	//key = node.key;
}

BST_Node::~BST_Node()
{
	delete left;
	delete right;
}

BST_Node& BST_Node::operator= (BST_Node& node)
{
	right = node.right;
	left = node.left;
	//key = node.key;
	return *this;
}

void BST_Node::setLeft(BST_Node* node)
{
	this->left = node;
}

void BST_Node::setRight(BST_Node* node)
{
	this->right = node;
}

yea i have an insert function already

bool BST::insert(BST_Node* &subRoot, Key key)
{
	BST_Node* node = new BST_Node(key);
	if(!subRoot)
	{
		subRoot = node;
		return true;
	}
	if(key == root->getKey())
	{
		return false;
		delete node;
	}
	if(key < subRoot->getKey())
	{
		if(subRoot->getLeft() == NULL)
		{
			root->setLeft(new BST_Node(key));
		}
		else
		{
			insert(subRoot->getRight(), key.data);
		}
	}
}

So just use the insert function in main.

The only thing I would do different is to use ofstream and ifstream for file i/o. And avoid anything with (EOF) like the plague.

Depending how your file is structured, will determine how you read it in. I'm assuming it looks something like this:

file.txt

Smith Chris
Jones Antony
Anderson Clive

Therefore you could read in each line into the binary search tree, using the getline command?

I need some help to read data from file to BST

/*
Name: Nguyen Ngoc Hoang
Student COde: 08020167
K53D- UET- VNU
Assigment 01
DSA
*/
#include<iostream>
#include<string>
#include<fstream>
#include<algorithm>
#include<iomanip>

using namespace std;

struct Data  // Data include keyword and number of occurrences
{
  string key;
  int count;
};

struct Node //A Node inclues Data, left and right
{
	Data data;
	Node* left;
	Node* right;
	Node(Data d,Node* l,Node* r)
    {
        data=d;
        left=l;
        right=r;
    }
};

class BSTree
{
private:
    static const int N = 100;
	Node *root;
public:
	//Construct an empty BSTree
	BSTree()
	{
		root=NULL;
	}
	//Create a BSTree from a file
	BSTree(BSTree &T , char *input)
	{
		ifstream fin;
		fin.open(input);
		if(!fin.good())
		{
		    cout<<"Error!File wordcount.in is not exits!"<<endl;
		    cout<<"Please check again !"<<endl;
		}
		Data getdata;
		getdata.count=1;
		string keyword;
		while(fin.good())
		{
		    fin>>keyword;
		    strcpy(keyword,getdata.key);
			T.InsertData(getdata);
		}
		fin.close();
	}
	//Destruct the BSTree
//	~BSTree();
	int IsEmpty();
	//Print all values of nodes inoder traversal
	void PrintTree(char* output);
	void Print_Tree(Node*,char* output);
	//Insert a value to BSTree
	void InsertData(Data DataInsert);
	void AddNode(Node *v,Data DataInsert);
};
int BSTree::IsEmpty()
{
    return root==NULL;
}
void BSTree::PrintTree(char* output)
{
    Print_Tree(root,output);
}
void BSTree::Print_Tree(Node* p,char* output)
{
    ofstream fout;
    fout.open(output);
    if(p!=NULL)
    {
        Print_Tree(p->left,output);
        fout<<p->data.key<<"\t";
        fout<<p->data.count<<endl;
        //fout<<"hoang huong";
        Print_Tree(p->right,output);
    }
    fout.close();
}

void BSTree::InsertData(Data DataInsert)
{
    if(root==NULL)  root=new Node(DataInsert,NULL,NULL );
    else    AddNode(root,DataInsert);
}
void BSTree::AddNode(Node *v,Data ValueInsert)
{

    if(v->data.key==ValueInsert.key)
    {
        ValueInsert.count++;
        return;
    }
    else
    {
        if(v->data.key > ValueInsert.key)
        {
            if(v->left!=NULL)   AddNode(v->left,ValueInsert);
            else    v->left=new Node(ValueInsert,NULL,NULL);
        }
        else
        {
            if(v->right!=NULL)  AddNode(v->right,ValueInsert);
            else    v->right=new Node(ValueInsert,NULL,NULL);
        }
    }
}
//main function
int main()
{
    BSTree T;
    BSTree Tree = BSTree(T ,"wordcount.in");
    T.PrintTree("wordcount.out");
}






//count the number of Node
int CountNode(Node* root)
{
    if(root=NULL)   return 0;
    else
    {
        int count=1;
        return CountNode(root->left)+CountNode(root->right);
    }
}
//Compare key of Node with a string
bool Compare(Node* n, string s)
{
    while(true)
    {
        if (n==NULL)    return false;
        else if(s==(n->data).key)    return true;
        else if(s<n->data.key)  n=n->left;
        else    n=n->right;

    }
}
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