ыы

#include <iostream>
#include <fstream>
#include <queue>
using namespace std;

class TreeNode {
public:
    TreeNode(int key) : Key(key), Left(0), Right(0) {}
    int Key;
    TreeNode* Left;
    TreeNode* Right;
};

class Tree {
public:
    Tree() :Root(0) {
    }
    ~Tree() {
        DestroyTreeNode(Root);
    }
    void Insert(int n);
    void LeftStraightPrint(TreeNode* root) {
        if (root = NULL) {
            return;
        }
        cout << root->Key << endl;
        LeftStraightPrint(root->Left);
        LeftStraightPrint(root->Right);
    };
    TreeNode *get_root() {
        return Root;
    }
private:
    static void DestroyTreeNode(TreeNode* tn) {
        if (tn) {
            DestroyTreeNode(tn->Left);
            DestroyTreeNode(tn->Right);
            delete tn;
        }
    }
private:
    TreeNode* Root;
};

void Tree::Insert(int n) {
    TreeNode** cur = &Root;
    while (*cur) {
        TreeNode& tn = **cur;
        if (n < tn.Key)
            cur = &tn.Left;
        else if (n > tn.Key)
            cur = &tn.Right;
        else return;
    }
    *cur = new TreeNode(n);
}

int main() {
    ifstream fin("input.txt");
    ofstream fout("output.txt");

    Tree MyTree;
    int temp;
    while (!fin.eof()) {
        fin >> temp;
        MyTree.Insert(temp);
    }
    MyTree.LeftStraightPrint(MyTree.get_root());

    fin.close();
    fout.close();
    system("pause");
    return 0;
}