commit b0111fce8ac1ce69aeba2a68e7df9070fd40fa2e
Author: tienthieusac <39063457+tienthieusac@users.noreply.github.com>
Date:   Wed Oct 3 20:45:35 2018 +0700

    Init

diff --git a/Lab1_1.cpp b/Lab1_1.cpp
new file mode 100644
index 0000000..d157022
--- /dev/null
+++ b/Lab1_1.cpp
@@ -0,0 +1,27 @@
+#include <iostream>
+using namespace std;
+bool isLeapYear(int n)
+{
+	if ((n % 4 == 0 && n % 100 != 0) || n % 400 == 0)
+	{
+		return true;
+	}
+	return false;
+}
+int main()
+{
+	int n;
+	cout << "Nhap so nam:" << endl;
+	cin >> n;
+	if (isLeapYear(n))
+	{
+		cout << "YES";
+	}
+	else
+	{
+		cout << "NO";
+	}
+	cout << endl;
+	system("pause");
+	return 0;
+}
\ No newline at end of file
diff --git a/Lab1_2a.cpp b/Lab1_2a.cpp
new file mode 100644
index 0000000..1c633df
--- /dev/null
+++ b/Lab1_2a.cpp
@@ -0,0 +1,79 @@
+#include <iostream>
+using namespace std;
+void nhapMatran(int *arr, int r, int c)
+{
+	for (int i = 0; i < r; i++)
+	{
+		for (int j = 0; j < c; j++)
+		{
+			cout << "Nhap phan tu tai hang " << i + 1 << ", cot " << j + 1 << ":";
+			cin >> *(arr + r*i + j);
+		}
+	}
+}
+void hienthiMatran(int *arr, int r, int c)
+{
+	for (int i = 0; i < r; i++)
+	{
+		for (int j = 0; j < c; j++)
+		{
+			cout << *(arr + r * i + j) << "\t";
+		}
+		cout << endl;
+	}
+}
+void nhanMatran(int *a, int ar, int ac, int *b, int br, int bc, int *c)
+{
+	for (int i = 0; i < ar; i++)
+	{
+		for (int j = 0; j < bc; j++)
+		{
+			*(c + ar * i + j) = 0;
+		}
+	}
+	for (int i = 0; i < ar; i++)
+	{
+		for (int j = 0; j < bc; j++)
+		{
+			for (int k = 0; k < ac; k++)
+			{
+				*(c + ar * i + j) += (*(a + ar * i + k)) * (*(b + ac * k + j));
+			}
+		}
+	}
+}
+int main()
+{
+	const int ar = 3;
+	const int ac = 3;
+	const int br = 3;
+	const int bc = 3;
+	int a[ar][ac] =
+	{
+		{1, 2, 3},
+		{4, 5, 6},
+		{7, 8, 9}
+	};
+	int b[br][bc] =
+	{
+		{1, 2, 3},
+		{4, 5, 6},
+		{7, 8, 9}
+	};
+	int c[ar][bc];
+	/*
+	cout << "Nhap vao ma tran A[" << ar << "][" << ac << "]:" << endl;
+	nhapMatran(*a, ar, ac);
+	cout << "Nhap vao ma tran B[" << br << "][" << bc << "]:" << endl;
+	nhapMatran(*b, br, bc);
+	*/
+	cout << "Ma tran A:" << endl;
+	hienthiMatran(*a, ar, ac);
+	cout << "Ma tran B:" << endl;
+	hienthiMatran(*b, ar, ac);
+	cout << "Ma tran C = A*B:" << endl;
+	nhanMatran(*a, ar, ac, *b, br, bc, *c);
+	hienthiMatran(*c, ar, bc);
+	system("pause");
+	return 0;
+}
\ No newline at end of file
diff --git a/Lab1_2b.cpp b/Lab1_2b.cpp
new file mode 100644
index 0000000..3755899
--- /dev/null
+++ b/Lab1_2b.cpp
@@ -0,0 +1,93 @@
+#include <iostream>
+using namespace std;
+void nhapMatran(int **arr, int r, int c)
+{
+	for (int i = 0; i < r; i++)
+	{
+		for (int j = 0; j < c; j++)
+		{
+			cout << "Nhap phan tu tai hang " << i + 1 << ", cot " << j + 1 << ":";
+			cin >> arr[i][j];
+		}
+	}
+}
+void hienthiMatran(int **arr, int r, int c)
+{
+	for (int i = 0; i < r; i++)
+	{
+		for (int j = 0; j < c; j++)
+		{
+			cout << arr[i][j] << "\t";
+		}
+		cout << endl;
+	}
+}
+bool nhanMatran(int **a, int ar, int ac, int **b, int br, int bc, int **c, int &cr, int &cc)
+{
+	if (ac == br)
+	{
+		for (int i = 0; i < cr; i++)
+		{
+			for (int j = 0; j < cc; j++)
+			{
+				c[i][j] = 0;
+				for (int k = 0; k < ac; k++)
+				{
+					c[i][j] += a[i][k] * b[k][j];
+				}
+			}
+		}
+		return true;
+	}
+	else
+	{
+		return false;
+	}
+}
+int main()
+{
+	int **a, **b, **c;
+	int ar, ac, br, bc, cr, cc;
+	cout << "Nhap vao so hang cua ma tran A:";
+	cin >> ar;
+	cout << "Nhap vao so cot cua ma tran A:";
+	cin >> ac;
+	a = new int*[ar];
+	for (int i = 0; i < ar; i++)
+	{
+		a[i] = new int[ac];
+	}
+	nhapMatran(a, ar, ac);
+	cout << "Nhap vao so hang cua ma tran B:";
+	cin >> br;
+	cout << "Nhap vao so cot cua ma tran B:";
+	cin >> bc;
+	b = new int*[br];
+	for (int i = 0; i < br; i++)
+	{
+		b[i] = new int[bc];
+	}
+	nhapMatran(b, br, bc);
+	cr = ar;
+	cc = bc;
+	c = new int*[cr];
+	for (int i = 0; i < cr; i++)
+	{
+		c[i] = new int[cc];
+	}
+	cout << "Ma tran A[" << ar << "][" << ac << "]:" << endl;
+	hienthiMatran(a, ar, ac);
+	cout << "Ma tran B[" << br << "][" << bc << "]:" << endl;
+	hienthiMatran(b, ar, ac);
+	cout << "Ma tran C = A*B:" << endl;
+	if (nhanMatran(a, ar, ac, b, br, bc, c, cr, cc))
+	{
+		hienthiMatran(c, cr, cc);
+	}
+	else
+	{
+		cout << "Khong the nhan hai ma tran voi kich co " << ar << "*" << ac << " va " << br << "*" << bc << "!" << endl;
+	}
+	system("pause");
+	return 0;
+}
\ No newline at end of file
diff --git a/Lab1_3a.cpp b/Lab1_3a.cpp
new file mode 100644
index 0000000..85264f1
--- /dev/null
+++ b/Lab1_3a.cpp
@@ -0,0 +1,24 @@
+#include <iostream>
+using namespace std;
+long pow(int n, int m)
+{
+	long p = 1;
+	for (int i = 0; i < m; i++)
+	{
+		p *= n;
+	}
+	return p;
+}
+int main()
+{
+	int n, m;
+	long p;
+	cout << "Nhap co so: ";
+	cin >> n;
+	cout << "Nhap so mu: ";
+	cin >> m;
+	p = pow(n, m);
+	cout << "n ^ m = " << p << endl;
+	system("pause");
+	return 0;
+}
\ No newline at end of file
diff --git a/Lab1_3b.cpp b/Lab1_3b.cpp
new file mode 100644
index 0000000..71c910c
--- /dev/null
+++ b/Lab1_3b.cpp
@@ -0,0 +1,26 @@
+#include <iostream>
+using namespace std;
+long pow(int n, int m)
+{
+	if (m == 0)
+	{
+		return 1;
+	}
+	else
+	{
+		return n * pow(n, m - 1);
+	}
+}
+int main()
+{
+	int n, m;
+	long p;
+	cout << "Nhap co so: ";
+	cin >> n;
+	cout << "Nhap so mu: ";
+	cin >> m;
+	p = pow(n, m);
+	cout << "n ^ m = " << p << endl;
+	system("pause");
+	return 0;
+}
\ No newline at end of file
diff --git a/Lab1_4a.cpp b/Lab1_4a.cpp
new file mode 100644
index 0000000..f276d67
--- /dev/null
+++ b/Lab1_4a.cpp
@@ -0,0 +1,32 @@
+#include <iostream>
+#include <string>
+using namespace std;
+int a(string s1, string s2)
+{
+	if (s1 == s2)
+	{
+		return 0;
+	}
+	int l = (s1.length() < s2.length()) ? s1.length() : s2.length();
+	for (int i = 0; i < l; i++)
+	{
+		if (s1[i] != s2[i])
+		{
+			return i + 1;
+		}
+	}
+	return l + 1;
+}
+int main()
+{
+	string s1, s2;
+	int n;
+	cout << "Nhap chuoi dau tien:" << endl;
+	getline(cin, s1);
+	cout << "Nhap chuoi thu hai:" << endl;
+	getline(cin, s2);
+	n = a(s1, s2);
+	cout << "Ket qua la: " << n << endl;
+	system("pause");
+	return 0;
+}
\ No newline at end of file
diff --git a/Lab1_4b.cpp b/Lab1_4b.cpp
new file mode 100644
index 0000000..98756e2
--- /dev/null
+++ b/Lab1_4b.cpp
@@ -0,0 +1,36 @@
+#include <iostream>
+#include <string>
+using namespace std;
+char* b(string s, char c)
+{
+	int l = (int)s.length();
+	for (int i = 0; i < l; i++)
+	{
+		if (s[i] == c)
+		{
+			return &s[i];
+		}
+	}
+	return 0;
+}
+int main()
+{
+	string s;
+	char c;
+	char* ptr;
+	cout << "Nhap chuoi:" << endl;
+	getline(cin, s);
+	cout << "Nhap ki tu:" << endl;
+	cin >> c;
+	ptr = b(s, c);
+	if (ptr != 0)
+	{
+		cout << "Dia chi cua ki tu la: " << (void *) ptr << endl;
+	}
+	else
+	{
+		cout << "Khong tim thay ki tu trong chuoi!" << endl;
+	}
+	system("pause");
+	return 0;
+}
\ No newline at end of file
diff --git a/Lab1_4c.cpp b/Lab1_4c.cpp
new file mode 100644
index 0000000..e968a1f
--- /dev/null
+++ b/Lab1_4c.cpp
@@ -0,0 +1,52 @@
+#include <iostream>
+#include <string>
+using namespace std;
+char* c(string s1, string s2)
+{
+	int l1 = (int)s1.length();
+	int l2 = (int)s2.length();
+	if (l1 > l2)
+	{
+		return 0;
+	}
+	for (int i = 0; i <= l2 - l1; i++)
+	{
+		int j = 0;
+		while (j < l1)
+		{
+			if (s2[i + j] != s1[j])
+			{
+				break;
+			}
+			else
+			{
+				j++;
+			}
+		}
+		if (j == l1)
+		{
+			return &s2[i];
+		}
+	}
+	return 0;
+}
+int main()
+{
+	string s1, s2;
+	char* ptr;
+	cout << "Nhap chuoi thu nhat:" << endl;
+	getline(cin, s1);
+	cout << "Nhap chuoi thu hai:" << endl;
+	getline(cin, s2);
+	ptr = c(s1, s2);
+	if (ptr != 0)
+	{
+		cout << "Dia chi can biet la: " << (void *)ptr << endl;
+	}
+	else
+	{
+		cout << "Chuoi 1 khong phai la chuoi con cua chuoi 2!" << endl;
+	}
+	system("pause");
+	return 0;
+}
\ No newline at end of file
diff --git a/Lab1_5.cpp b/Lab1_5.cpp
new file mode 100644
index 0000000..afb58a8
--- /dev/null
+++ b/Lab1_5.cpp
@@ -0,0 +1,60 @@
+#include <iostream>
+#include <iomanip>
+using namespace std;
+class candidate
+{
+public:
+	int id;
+	char* name;
+private:
+	float math, physics, chemistry;
+public:
+	candidate(int id, char* name, float math, float physics, float chemistry)
+	{
+		this->id = id;
+		this->name = name;
+		this->math = math;
+		this->physics = physics;
+		this->chemistry = chemistry;
+	}
+	~candidate()
+	{
+		id = 0;
+		delete[] name;
+		name = NULL;
+		math = 0;
+		physics = 0;
+		chemistry = 0;
+	}
+	float total_grade()
+	{
+		return (math + physics + chemistry);
+	}
+};
+int main()
+{
+	candidate *t;
+	float tongdiem;
+	int id;
+	char *name = new char[256];
+	float math, physics, chemistry;
+	cout << "Nhap id: " << endl;
+	cin >> id;
+	cout << "Nhap ten: " << endl;
+	cin.clear();
+	cin.ignore(999, '\n');
+	cin.getline(name, 256);
+	cout << "Nhap diem Toan: " << endl;
+	cin >> math;
+	cout << "Nhap diem Ly: " << endl;
+	cin >> physics;
+	cout << "Nhap diem Hoa: " << endl;
+	cin >> chemistry;
+	t = new candidate(id, name, math, physics, chemistry);
+	tongdiem = t->total_grade();
+	cout << "Tong diem: " << setprecision(4) << tongdiem << endl;
+	delete t;
+	t = NULL;
+	system("pause");
+	return 0;
+}
\ No newline at end of file
diff --git a/Lab2.cpp b/Lab2.cpp
new file mode 100644
index 0000000..08ae5f7
--- /dev/null
+++ b/Lab2.cpp
@@ -0,0 +1,196 @@
+#include <algorithm>
+#include <cmath>
+#include <fstream>
+#include <iomanip>
+#include <iostream>
+#include <sstream>
+#include <string>
+#define MEET_DISTANCE 50	//Fix from 10 to 50
+#define MEET_TIME 5000		//Fix from 4000 to 5000
+using namespace std;
+struct Position
+{
+	double latitude, longitude;
+	unsigned long long time;
+	Position* next;
+	Position()
+	{
+		latitude = 0;
+		longitude = 0;
+		time = 0;
+		next = NULL;
+	}
+};
+void append(Position* &start, Position* new_position)
+{
+	if (start == NULL)
+	{
+		start = new_position;
+		return;
+	}
+	Position* temp = start;
+	while (temp->next != NULL)
+	{
+		temp = temp->next;
+	}
+	temp->next = new_position;
+}
+Position* readFromFile(string filename)
+{
+	fstream file;
+	file.open(filename, ios::in);
+	if (!file.is_open())
+	{
+		cout << "Loi doc file!" << endl;
+		return NULL;
+	}
+	string line;
+	Position* start, *new_position;
+	start = NULL;
+	while (getline(file, line))
+	{
+		replace(line.begin(), line.end(), ',', ' ');
+		new_position = new Position;
+		stringstream ss;
+		ss.str(line);
+		double time;
+		ss >> new_position->latitude >> new_position->longitude >> time;
+		new_position->time = (unsigned long long) time;
+		append(start, new_position);
+	}
+	file.close();
+	return start;
+}
+void writeToFile(string filename, Position* start)
+{
+	fstream file;
+	file.open(filename, ios::out);
+	Position* temp = start;
+	while (temp != NULL)
+	{
+		file << setprecision(10) << temp->latitude << "," << temp->longitude << "," << temp->time << endl;
+		temp = temp->next;
+	}
+	file.close();
+}
+void findMin(Position* start, Position* &preMin, Position* &min)
+{
+	if (start == NULL)
+	{
+		preMin = NULL;
+		min = NULL;
+		return;
+	}
+	Position* temp = start;
+	preMin = NULL;
+	min = start;
+	while (temp->next != NULL)
+	{
+		if (temp->next->time < min->time)
+		{
+			preMin = temp;
+			min = preMin->next;
+		}
+		temp = temp->next;
+	}
+}
+void sortList(Position* &start)
+{
+	if (start == NULL)
+	{
+		return;
+	}
+	if (start->next == NULL)
+	{
+		return;
+	}
+	Position *newList, *preMin, *min;
+	newList = NULL;
+	while (start != NULL)
+	{
+		findMin(start, preMin, min);
+		append(newList, min);
+		if (min == start)
+		{
+			start = min->next;
+		}
+		else
+		{
+			preMin->next = min->next;
+		}
+		min->next = NULL;
+	}
+	start = newList;
+}
+double distance(Position* pos_1, Position* pos_2)
+{
+	return pow(10, 5)*sqrt(pow(pos_1->latitude - pos_2->latitude, 2) + pow(pos_1->longitude - pos_2->longitude, 2));
+}
+double loopLengthOfPath(Position* start)
+{
+	if (start == NULL)
+	{
+		return 0;
+	}
+	double length = 0;
+	Position* temp = start;
+	while (temp->next != NULL)
+	{
+		length += distance(temp, temp->next);
+		temp = temp->next;
+	}
+	return length;
+}
+double recursionLengthOfPath(Position* start)
+{
+	if (start == NULL)
+	{
+		return 0;
+	}
+	if (start->next == NULL)
+	{
+		return 0;
+	}
+	double length = distance(start, start->next);
+	return length + recursionLengthOfPath(start->next);
+}
+bool checkMeeting(Position* start_1, Position* start_2)
+{
+	if (start_1 == NULL || start_2 == NULL)
+	{
+		return false;
+	}
+	Position* temp_1 = start_1;
+	Position* temp_2 = start_2;
+	while (abs((long long) (temp_1->time - temp_2->time)) > MEET_TIME || distance(temp_1, temp_2) > MEET_DISTANCE)
+	{
+		if (temp_1->time > temp_2->time)
+		{
+			temp_2 = temp_2->next;
+		}
+		else
+		{
+			temp_1 = temp_1->next;
+		}
+		if (temp_1 == NULL || temp_2 == NULL)
+		{
+			return false;
+		}
+	}
+	return true;
+}
+int main()
+{
+	Position* start = readFromFile("position.csv");
+	Position* start_2 = readFromFile("position_2.csv");
+	sortList(start);
+	sortList(start_2);
+	cout << loopLengthOfPath(start) << endl;
+	cout << recursionLengthOfPath(start_2) << endl;
+	string out = checkMeeting(start, start_2) ? "YES" : "NO";
+	cout << out << endl;
+	writeToFile("sorted.csv", start);
+	writeToFile("sorted_2.csv", start_2);
+	system("pause");
+	return 0;
+}
\ No newline at end of file
diff --git a/Lab3.cpp b/Lab3.cpp
new file mode 100644
index 0000000..620d7dd
--- /dev/null
+++ b/Lab3.cpp
@@ -0,0 +1,275 @@
+#include <algorithm>
+#include <iomanip>
+#include <iostream>
+#include <fstream>
+#include <sstream>
+
+using namespace std;
+
+struct ProductCategory
+{
+	string ID;
+	string name;
+	ProductCategory *next;
+};
+
+struct Product
+{
+	string ID;
+	string name;
+	int selling_price;
+	int importing_price;
+	double quantity;
+	ProductCategory *product_category;
+	Product *next;
+};
+
+void releaseCategory(ProductCategory* &category_head)
+{
+	if (category_head != NULL)
+	{
+		ProductCategory* temp = category_head;
+		category_head = category_head->next;
+		delete temp;
+		releaseCategory(category_head);
+	}
+}
+
+void releaseProduct(Product* &head)
+{
+	if (head != NULL)
+	{
+		Product* temp = head;
+		head = head->next;
+		delete temp;
+		releaseProduct(head);
+	}
+}
+
+void appendCategory(ProductCategory* &category_head, ProductCategory* newcategory)
+{
+	if (category_head == NULL)
+	{
+		category_head = newcategory;
+		return;
+	}
+	ProductCategory *temp = category_head;
+	while (temp->next != NULL) temp = temp->next;
+	temp->next = newcategory;
+}
+
+void appendProduct(Product* &head, Product* new_product)
+{
+	if (head == NULL)
+	{
+		head = new_product;
+		return;
+	}
+	Product *temp = head;
+	while (temp->next != NULL) temp = temp->next;
+	temp->next = new_product;
+}
+
+void findProductCategory(ProductCategory* category_head, string ID, ProductCategory* &result)
+{
+	result = category_head;
+	while (result != NULL)
+	{
+		if (result->ID == ID)
+			return;
+		result = result->next;
+	}
+}
+
+void readFromFile(string filename, Product* &head, ProductCategory* &category_head)
+{
+	releaseCategory(category_head);
+	releaseProduct(head);
+	ifstream ifs;
+	ifs.open(filename, ifstream::in);
+	if (!ifs.is_open())
+	{
+		cout << "Loi doc file!" << endl;
+		return;
+	}
+	string line;
+	while (getline(ifs, line))
+	{
+		replace(line.begin(), line.end(), ',', ' ');
+		Product *new_product = new Product;
+		string ID, name;
+		istringstream iss;
+		iss.str(line);
+		iss >> new_product->ID
+			>> new_product->name
+			>> new_product->selling_price
+			>> new_product->importing_price
+			>> new_product->quantity
+			>> ID
+			>> name;
+		new_product->next = NULL;
+		findProductCategory(category_head, ID, new_product->product_category);
+		if (new_product->product_category == NULL)
+		{
+			ProductCategory *new_category = new ProductCategory;
+			new_category->ID = ID;
+			new_category->name = name;
+			new_category->next = NULL;
+			appendCategory(category_head, new_category);
+			new_product->product_category = new_category;
+		}
+		appendProduct(head, new_product);
+	}
+	ifs.close();
+}
+
+void writeProductToFile(string filename, Product* head)
+{
+	ofstream ofs;
+	ofs.open(filename, ofstream::out);
+	Product* temp = head;
+	while (temp != NULL)
+	{
+		ofs << setprecision(10)
+			<< temp->ID << ","
+			<< temp->name << ","
+			<< temp->selling_price << ","
+			<< temp->importing_price << ","
+			<< temp->quantity << ","
+			<< temp->product_category->ID << ","
+			<< temp->product_category->name
+			<< endl;
+		temp = temp->next;
+	}
+	ofs.close();
+}
+
+void printAllCategories(Product* head)
+{
+	int cnt = 0;
+	ProductCategory *category_head = NULL;
+	Product *temp = head;
+	while (temp != NULL)
+	{
+		ProductCategory *result = NULL;
+		findProductCategory(category_head, temp->product_category->ID, result);
+		if (result == NULL)
+		{
+			result = new ProductCategory;
+			result->ID = temp->product_category->ID;
+			result->name = temp->product_category->name;
+			result->next = NULL;
+			appendCategory(category_head, result);
+			++cnt;
+		}
+		temp = temp->next;
+	}
+	cout << cnt;
+	if (cnt > 1) cout << " categories";
+	else cout << " category";
+	cout << endl;
+	ProductCategory *tmp = category_head;
+	while (tmp != NULL)
+	{
+		cout << "----------------" << endl;
+		cout << "ID: " << tmp->ID << endl;
+		cout << "Name: " << tmp->name << endl;
+		tmp = tmp->next;
+	}
+	releaseCategory(category_head);
+}
+
+bool deleteProducts(Product* &head, double quantity)
+{
+	int cnt = 0;
+	Product *temp, *tmp;
+	while (head != NULL)
+	{
+		if (head->quantity < quantity)
+		{
+			tmp = head;
+			head = head->next;
+			delete tmp;
+			++cnt;
+		}
+		else break;
+	}
+	if (head != NULL)
+	{
+		temp = head;
+		while (temp->next != NULL)
+		{
+			if (temp->next->quantity < quantity)
+			{
+				tmp = temp->next;
+				temp->next = tmp->next;
+				delete tmp;
+				++cnt;
+				continue;
+			}
+			temp = temp->next;
+		}
+	}
+	return (cnt > 0);
+}
+
+double sellingFromFile(Product* &head, string filename)
+{
+	ifstream ifs;
+	double price = 0;
+	ifs.open(filename, ios::in);
+	if (!ifs.is_open())
+	{
+		cout << "Loi doc file" << endl;
+		return price;
+	}
+	string line;
+	while (getline(ifs, line))
+	{
+		replace(line.begin(), line.end(), ',', ' ');
+		istringstream iss;
+		string ID;
+		double quantity;
+		iss.str(line);
+		iss >> ID >> quantity;
+		Product *temp = head;
+		while (temp != NULL)
+		{
+			if (temp->ID == ID)
+			{
+				if (temp->quantity > quantity)
+				{
+					price += quantity * temp->selling_price;
+					temp->quantity -= quantity;
+				}
+				else
+				{
+					price += temp->quantity * temp->selling_price;
+					temp->quantity = 0;
+				}
+				break;
+			}
+			temp = temp->next;
+		}
+	}
+	ifs.close();
+	return price;
+}
+
+int main()
+{
+	Product *head = NULL;
+	ProductCategory *category_head = NULL;
+	readFromFile("ProductIn.csv", head, category_head);
+	double m = sellingFromFile(head, "SellingProduct.csv");
+	cout << "Tong so tien: " << m << endl;
+	printAllCategories(head);
+	bool b = deleteProducts(head, 5);
+	if (b)
+		cout << "Delete thanh cong!" << endl;
+	else
+		cout << "Delete khong thanh cong!" << endl;
+	writeProductToFile("ProductOut.csv", head);
+	system("pause");
+	return 0;
+}
\ No newline at end of file
diff --git a/Lab3_SampleData/ProductIn.csv b/Lab3_SampleData/ProductIn.csv
new file mode 100644
index 0000000..7e5e1f1
--- /dev/null
+++ b/Lab3_SampleData/ProductIn.csv
@@ -0,0 +1,10 @@
+C001,One,30,30,9.3,CO,Odd
+C002,Two,12,10,8,CE,Even
+C003,Three,25,25,8.5,CO,Odd
+C004,Four,20,16,7.7,CE,Even
+C005,Five,10,5,5.6,CO,Odd
+C006,Six,21,20,7.4,CE,Even
+C007,Seven,26,21,5.8,CO,Odd
+C008,Eight,27,27,5.6,CE,Even
+C009,Nine,23,21,7,CO,Odd
+C010,Ten,23,19,9.4,CE,Even
diff --git a/Lab3_SampleData/ProductOut.csv b/Lab3_SampleData/ProductOut.csv
new file mode 100644
index 0000000..80af4a0
--- /dev/null
+++ b/Lab3_SampleData/ProductOut.csv
@@ -0,0 +1,7 @@
+C001,One,30,30,9.3,CO,Odd
+C002,Two,12,10,7,CE,Even
+C003,Three,25,25,5.5,CO,Odd
+C006,Six,21,20,7.4,CE,Even
+C007,Seven,26,21,5.8,CO,Odd
+C009,Nine,23,21,7,CO,Odd
+C010,Ten,23,19,5.4,CE,Even
diff --git a/Lab3_SampleData/SellingProduct.csv b/Lab3_SampleData/SellingProduct.csv
new file mode 100644
index 0000000..a763912
--- /dev/null
+++ b/Lab3_SampleData/SellingProduct.csv
@@ -0,0 +1,9 @@
+C002,1
+C003,3
+C004,5
+C005,7
+C008,9
+C009,0
+C010,2
+C010,2
+CXXX,5
diff --git a/Lab4 (bak).cpp b/Lab4 (bak).cpp
new file mode 100644
index 0000000..ae8e1fe
--- /dev/null
+++ b/Lab4 (bak).cpp	
@@ -0,0 +1,228 @@
+#include <iostream>
+
+using namespace std;
+
+struct Node {
+    int data;
+    Node *next;
+};
+
+struct Stack {
+    Node *sTop;
+    int sCount;
+};
+
+struct Queue {
+    Node *qFront;
+    Node *qRear;
+    int qCount;
+};
+
+void createStack(Stack *&s)
+{
+    if (s != nullptr) {
+        while (s->sTop != nullptr) {
+            Node *temp = s->sTop;
+            s->sTop = s->sTop->next;
+            delete temp;
+        }
+        s->sCount = 0;
+        delete s;
+    }
+    s = new Stack;
+    s->sTop = nullptr;
+    s->sCount = 0;
+}
+
+void pushStack(Stack *&s, int data)
+{
+    if (s == nullptr)
+        return;
+    Node *temp = new Node;
+    if (temp == nullptr)
+        return;
+    temp->data = data;
+    temp->next = s->sTop;
+    s->sTop = temp;
+    s->sCount++;
+}
+
+void popStack(Stack *&s)
+{
+    if (s == nullptr)
+        return;
+    if (s->sCount == 0)
+        return;
+    Node *temp = s->sTop;
+    s->sTop = s->sTop->next;
+    delete temp;
+    s->sCount--;
+}
+
+int topStack(Stack *&s)
+{
+    if (s == nullptr)
+        return 0;
+    if (s->sCount == 0)
+        return 0;
+    return s->sTop->data;
+}
+
+bool isStackEmpty(Stack *s)
+{
+    if (s == nullptr)
+        return true;
+    return (s->sCount == 0);
+}
+
+bool isStackFull(Stack *s)
+{
+    Node *temp = new Node;
+    if (temp != nullptr) {
+        delete temp;
+        return false;
+    }
+    return true;
+}
+
+void clearStack(Stack *&s)
+{
+    while (!isStackEmpty(s))
+        popStack(s);
+}
+
+int sizeOfStack(Stack *s)
+{
+    if (s == nullptr)
+        return -1;
+    return s->sCount;
+}
+
+void createQueue(Queue *&q)
+{
+    if (q != nullptr) {
+        while (q->qRear != nullptr) {
+            Node *temp = q->qRear;
+            q->qRear = q->qRear->next;
+            delete temp;
+        }
+        while (q->qFront != nullptr) {
+            Node *temp = q->qFront;
+            q->qFront = q->qFront->next;
+            delete temp;
+        }
+    }
+    q = new Queue;
+    q->qCount = 0;
+    q->qFront = nullptr;
+    q->qRear = nullptr;
+}
+
+void enqueue(Queue *&q, int data)
+{
+    if (q == nullptr)
+        return;
+    Node *temp = new Node;
+    if (temp == nullptr)
+        return;
+    temp->next = q->qRear;
+    temp->data = data;
+    q->qRear = temp;
+    if (q->qCount == 0)
+        q->qFront = temp;
+    q->qCount++;
+}
+
+void dequeue(Queue *&q)
+{
+    if (q == nullptr)
+        return;
+    if (q->qCount == 0)
+        return;
+    Node *temp = nullptr;
+    if (q->qCount == 1) {
+        q->qRear = nullptr;
+    } else {
+        temp = q->qRear;
+        while (temp->next != q->qFront)
+            temp = temp->next;
+    }
+    delete q->qFront;
+    q->qFront = temp;
+    q->qCount--;
+}
+
+int queueFront(Queue *q)
+{
+    if (q == nullptr)
+        return 0;
+    if (q->qCount == 0)
+        return 0;
+    return q->qFront->data;
+}
+
+int queueRear(Queue *q)
+{
+    if (q == nullptr)
+        return 0;
+    if (q->qCount == 0)
+        return 0;
+    return q->qRear->data;
+}
+
+bool isQueueEmpty(Queue *q)
+{
+    if (q == nullptr)
+        return true;
+    return (q->qCount == 0);
+}
+
+bool isQueueFull(Queue *q)
+{
+    Node *temp = new Node;
+    if (temp != nullptr) {
+        delete temp;
+        return false;
+    }
+    return true;
+}
+
+void clearQueue(Queue *&q)
+{
+    while (!isQueueEmpty(q))
+        dequeue(q);
+}
+
+int sizeOfQueue(Queue *q)
+{
+    if (q == nullptr)
+        return -1;
+    return q->qCount;
+}
+
+void stackToQueue(Stack *&s, Queue *&q)
+{
+    createQueue(q);
+    while (!isStackEmpty(s)) {
+        int x = topStack(s);
+        popStack(s);
+        enqueue(q, x);
+    }
+}
+
+void queueToStack(Queue *&q, Stack *&s)
+{
+    createStack(s);
+    if (!isQueueEmpty(q)) {
+        Node *temp = q->qRear;
+        while (temp != nullptr) {
+            pushStack(s, temp->data);
+            temp = temp->next;
+        }
+    }
+}
+
+int main()
+{
+    return 0;
+}
diff --git a/Lab4.cpp b/Lab4.cpp
new file mode 100644
index 0000000..c563aaf
--- /dev/null
+++ b/Lab4.cpp
@@ -0,0 +1,399 @@
+#include <iostream>
+
+using namespace std;
+
+struct Node {
+    int data;
+    Node *next;
+    Node()
+    {
+        this->data = 0;
+        this->next = nullptr;
+    }
+    Node(int data)
+    {
+        this->data = data;
+        this->next = nullptr;
+    }
+    Node(int data, Node *next)
+    {
+        this->data = data;
+        this->next = next;
+    }
+    ~Node() {}
+};
+
+enum ErrorCode {
+    SUCCESS,
+    FAIL,
+    OVERFLOW,
+    UNDERFLOW
+};
+
+class Stack
+{
+private:
+    Node *sTop;
+    int sCount;
+public:
+    Stack()
+    {
+        this->sTop = nullptr;
+        this->sCount = 0;
+    }
+    ~Stack()
+    {
+        if (!this->isEmpty())
+            this->clear();
+    }
+    ErrorCode create();
+    ErrorCode push(int data);
+    ErrorCode pop();
+    ErrorCode top(int &data);
+    bool isEmpty();
+    bool isFull();
+    ErrorCode clear();
+    int size();
+};
+
+ErrorCode Stack::create()
+{
+    if (!this->isEmpty())
+        return this->clear();
+    return SUCCESS;
+}
+
+ErrorCode Stack::push(int data)
+{
+    if (this->isFull())
+        return OVERFLOW;
+    Node *temp = new Node(data, this->sTop);
+    this->sTop = temp;
+    temp = nullptr;
+    this->sCount++;
+    return SUCCESS;
+}
+
+ErrorCode Stack::pop()
+{
+    if (this->isEmpty())
+        return UNDERFLOW;
+    Node *temp = this->sTop;
+    this->sTop = this->sTop->next;
+    delete temp;
+    temp = nullptr;
+    this->sCount--;
+    return SUCCESS;
+}
+
+ErrorCode Stack::top(int &data)
+{
+    if (this->isEmpty()) {
+        data = 0;
+        return FAIL;
+    }
+    data = this->sTop->data;
+    return SUCCESS;
+}
+
+bool Stack::isEmpty()
+{
+    return (this->sCount == 0);
+}
+
+bool Stack::isFull()
+{
+    Node *temp = new Node;
+    if (temp != nullptr) {
+        delete temp;
+        temp = nullptr;
+        return false;
+    }
+    return true;
+}
+
+ErrorCode Stack::clear()
+{
+    while (!this->isEmpty()) {
+        this->pop();
+    }
+    return SUCCESS;
+}
+
+int Stack::size()
+{
+    return this->sCount;
+}
+
+class Queue
+{
+private:
+    Node *qFront;
+    Node *qRear;
+    int qCount;
+public:
+    Queue()
+    {
+        this->qFront = nullptr;
+        this->qRear = nullptr;
+        this->qCount = 0;
+    }
+    ~Queue()
+    {
+        if (!this->isEmpty())
+            this->clear();
+    }
+    ErrorCode create();
+    ErrorCode enqueue(int data);
+    ErrorCode dequeue();
+    ErrorCode queueFront(int &data);
+    ErrorCode queueRear(int &data);
+    bool isFull();
+    bool isEmpty();
+    ErrorCode clear();
+    int size();
+};
+
+ErrorCode Queue::create()
+{
+    if (!this->isEmpty())
+        return this->clear();
+    return SUCCESS;
+}
+
+ErrorCode Queue::enqueue(int data)
+{
+    if (this->isFull())
+        return OVERFLOW;
+    Node *temp = new Node(data, this->qRear);
+    qRear = temp;
+    temp = nullptr;
+    if (this->isEmpty()) {
+        qFront = qRear;
+    }
+    this->qCount++;
+    return SUCCESS;
+}
+
+ErrorCode Queue::dequeue()
+{
+    if (this->isEmpty())
+        return UNDERFLOW;
+    Node *temp = nullptr;
+    if (this->qCount == 1) {
+        this->qRear = nullptr;
+    } else {
+        temp = this->qRear;
+        while (temp->next != this->qFront)
+            temp = temp->next;
+    }
+    delete this->qFront;
+    this->qFront = temp;
+    this->qCount--;
+    return SUCCESS;
+}
+
+ErrorCode Queue::queueFront(int &data)
+{
+    if (this->isEmpty()) {
+        data = 0;
+        return FAIL;
+    }
+    data = this->qFront->data;
+    return SUCCESS;
+}
+
+ErrorCode Queue::queueRear(int &data)
+{
+    if (this->isEmpty()) {
+        data = 0;
+        return FAIL;
+    }
+    data = this->qRear->data;
+    return SUCCESS;
+}
+
+bool Queue::isEmpty()
+{
+    return (this->qCount == 0);
+}
+
+bool Queue::isFull()
+{
+    Node *temp = new Node;
+    if (temp != nullptr) {
+        delete temp;
+        temp = nullptr;
+        return false;
+    }
+    return true;
+}
+
+ErrorCode Queue::clear()
+{
+    while (!this->isEmpty())
+        this->dequeue();
+    return SUCCESS;
+}
+
+int Queue::size()
+{
+    return this->qCount;
+}
+
+void stackToQueue(Stack &s, Queue &q)
+{
+    q.create();
+    while (!s.isEmpty()) {
+        int data;
+        s.top(data);
+        q.enqueue(data);
+        s.pop();
+    }
+}
+
+void queueToStack(Queue &q, Stack &s)
+{
+    s.create();
+    Queue qTemp;
+    Stack sTemp;
+    while (!q.isEmpty()) {
+        int data;
+        q.queueFront(data);
+        sTemp.push(data);
+        qTemp.enqueue(data);
+        q.dequeue();
+    }
+    while (!qTemp.isEmpty()) {
+        int data;
+        qTemp.queueFront(data);
+        q.enqueue(data);
+        qTemp.dequeue();
+    }
+    while (!sTemp.isEmpty()) {
+        int data;
+        sTemp.top(data);
+        s.push(data);
+        sTemp.pop();
+    }
+}
+
+void printStack(Stack &s) //print Stack from top to base
+{
+    Stack sTemp;
+    while (!s.isEmpty()) {
+        int data;
+        s.top(data);
+        cout << data << " ";
+        sTemp.push(data);
+        s.pop();
+    }
+    while (!sTemp.isEmpty()) {
+        int data;
+        sTemp.top(data);
+        s.push(data);
+        sTemp.pop();
+    }
+    cout << endl;
+}
+
+void printQueue(Queue &q) //print Queue from front to rear
+{
+    Stack sTemp;
+    Queue qTemp;
+    while (!q.isEmpty()) {
+        int data;
+        q.queueFront(data);
+        cout << data << " ";
+        sTemp.push(data);
+        qTemp.enqueue(data);
+        q.dequeue();
+    }
+    while (!qTemp.isEmpty()) {
+        int data;
+        qTemp.queueFront(data);
+        q.enqueue(data);
+        qTemp.dequeue();
+    }
+    cout << endl;
+}
+
+int main()
+{
+    string errorCodeString[] = {
+        "SUCCESS",
+        "FAIL",
+        "OVERFLOW",
+        "UNDERFLOW"
+    };
+    string output;
+    ErrorCode errorCode;
+    int data;
+    cout << "Init Stack:" << endl;
+    Stack s;
+    Queue q;
+    Stack sTemp;
+    Queue qTemp;
+    for (int i = 0; i < 10; ++i) {
+        s.push(i);
+        printStack(s);
+    }
+    cout << "Size of Stack: " << s.size() << endl;
+    output = s.isFull() ? "YES" : "NO";
+    cout << "Is Stack full?: " << output << endl;
+    cout << "Clear and print Stack:" << endl;
+    s.clear();
+    printStack(s);
+    output = s.isEmpty() ? "YES" : "NO";
+    cout << "Is Stask empty?: " << output << endl;
+    errorCode = s.pop();
+    cout << "ErrorCode when pop Stack again: "
+         << errorCodeString[errorCode] << endl;
+    errorCode = s.top(data);
+    cout << "ErrorCode when top an empty Stack: "
+         << errorCodeString[errorCode] << endl;
+    cout << "Init Queue:" << endl;
+    for (int i = 0; i < 10; ++i) {
+        q.enqueue(i);
+        printQueue(q);
+    }
+    cout << "Size of Queue: " << q.size() << endl;
+    output = q.isFull() ? "YES" : "NO";
+    cout << "Is Queue full?: " << output << endl;
+    cout << "Clear and print Queue:" << endl;
+    q.clear();
+    printQueue(q);
+    output = q.isEmpty() ? "YES" : "NO";
+    cout << "Is Queue empty?: " << output << endl;
+    errorCode = q.dequeue();
+    cout << "ErrorCode when dequeue Queue again: "
+         << errorCodeString[errorCode] << endl;
+    errorCode = q.queueFront(data);
+    cout << "ErrorCode when queueFront an empty Queue: "
+         << errorCodeString[errorCode] << endl;
+    errorCode = q.queueRear(data);
+    cout << "ErrorCode when queueRear an empty Queue: "
+         << errorCodeString[errorCode] << endl;
+    cout << "Init Stack and Queue again:" << endl;
+    for (int i = 0; i < 10; i++) {
+        s.push(i);
+        q.enqueue(i);
+    }
+    cout << "Stack: ";
+    printStack(s);
+    cout << "Queue: ";
+    printQueue(q);
+    cout << "Use stackToQueue to create new Queue:" << endl;
+    stackToQueue(s, qTemp);
+    cout << "New Queue: ";
+    printQueue(qTemp);
+    cout << "Stack after: ";
+    printStack(s);
+    cout << "Use queueToStack to create new Stack" << endl;
+    queueToStack(q, sTemp);
+    cout << "New Stack: ";
+    printStack(sTemp);
+    cout << "Queue after: ";
+    printQueue(q);
+    return 0;
+}
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..62c82e4
--- /dev/null
+++ b/README.md
@@ -0,0 +1,2 @@
+# CTDL-GT
+Code trong mon Cau truc du lieu va giai thuat (HK181)
diff --git a/Tut2_1.cpp b/Tut2_1.cpp
new file mode 100644
index 0000000..3c1b144
--- /dev/null
+++ b/Tut2_1.cpp
@@ -0,0 +1,44 @@
+#include <iostream>
+using namespace std;
+bool isPrime(int num) {
+	if (num < 2) {
+		return false;
+	}
+	int i;
+	for (i = 2; i*i <= num; i++) {
+		if (num % i == 0) return false;
+	}
+	return true;
+}
+void onePrime(int * arr, int n) {
+	if (n == 0)
+	{
+		return;
+	}
+	if (isPrime(arr[n - 1]))
+	{
+		cout << arr[n - 1] << endl;
+		return;
+	}
+	onePrime(arr, n - 1);
+}
+void allPrime(int * arr, int n) {
+	if (n == 0)
+	{
+		cout << endl;
+		return;
+	}
+	if (isPrime(arr[n - 1]))
+	{
+		cout << arr[n - 1] << " ";
+	}
+	allPrime(arr, n - 1);
+}
+int main()
+{
+	int arr[] = {1, 3, 5, 7, 9};
+	onePrime(arr, 5);
+	allPrime(arr, 5);
+	system("pause");
+	return 0;
+}
\ No newline at end of file
diff --git a/Tut2_2.cpp b/Tut2_2.cpp
new file mode 100644
index 0000000..1cd3f1d
--- /dev/null
+++ b/Tut2_2.cpp
@@ -0,0 +1,49 @@
+#include <iostream>
+using namespace std;
+struct node {
+	int data;
+	node *next = NULL;
+};
+int myMaxFunc(node* head, int maxVal) {
+	if (head == NULL)
+	{
+		return maxVal;
+	}
+	if (head->data > maxVal)
+	{
+		maxVal = head->data;
+	}
+	return myMaxFunc(head->next, maxVal);
+}
+int main()
+{
+	node *a, *b, *c, *d, *e, *f, *g;
+	node *head;
+	g = new node();
+	g->data = 7;
+	g->next = NULL;
+	f = new node();
+	f->data = 2;
+	f->next = g;
+	e = new node();
+	e->data = 100;
+	e->next = f;
+	d = new node();
+	d->data = 3;
+	d->next = e;
+	c = new node();
+	c->data = 9;
+	c->next = d;
+	b = new node();
+	b->data = 5;
+	b->next = c;
+	a = new node();
+	a->data = -11;
+	a->next = b;
+	head = new node();
+	//head->data = 0;
+	head->next = a;
+	cout << myMaxFunc(head, INT_MIN) << endl;
+	system("pause");
+	return 0;
+}
\ No newline at end of file
diff --git a/Tut2_3.cpp b/Tut2_3.cpp
new file mode 100644
index 0000000..114e99c
--- /dev/null
+++ b/Tut2_3.cpp
@@ -0,0 +1,105 @@
+#include <iostream>
+using namespace std;
+void draw_ch(int k)
+{
+	if (k > 1)
+	{
+		cout << "_";
+		draw_ch(k - 1);
+	}
+}
+void draw_num(int k, int n)
+{
+	if (k <= n)
+	{
+		cout << k;
+		draw_num(k + 1, n);
+	}
+}
+void draw1Line(int k, int n, bool b)
+{
+	draw_ch(k);
+	draw_num(k, n);
+	cout << endl;
+	if (b == 0)
+	{
+		if (k > n / 2 + 1)
+		{
+			draw1Line(k - 1, n, 0);
+		}
+		else
+		{
+			if (n % 2)
+			{
+				draw1Line(k + 1, n, 1);
+			}
+			else
+			{
+				draw1Line(k, n, 1);
+			}
+		}
+	}
+	else
+	{
+		if (k >= n)
+		{
+			return;
+		}
+		else
+		{
+			draw1Line(k + 1, n, 1);
+		}
+	}
+}
+void recursiveTriangle(int N)
+{
+	draw1Line(N, N, 0);
+}
+void loopTriangle(int N)
+{
+	int k, i;
+	k = N;
+	for (; k > N/2; k--)
+	{
+		i = 1;
+		for (; i < k; i++)
+		{
+			cout << "_";
+		}
+		for (; i <= N; i++)
+		{
+			cout << i;
+		}
+		cout << endl;
+	}
+	if (N % 2)
+	{
+		k+= 2;
+	}
+	else
+	{
+		k++;
+	}
+	for (; k <= N; k++)
+	{
+		i = 1;
+		for (; i < k; i++)
+		{
+			cout << "_";
+		}
+		for (; i <= N; i++)
+		{
+			cout << i;
+		}
+		cout << endl;
+	}
+}
+int main()
+{
+	int n;
+	cin >> n;
+	recursiveTriangle(n);
+	loopTriangle(n);
+	system("pause");
+	return 0;
+}
\ No newline at end of file
diff --git a/Tut2_4.cpp b/Tut2_4.cpp
new file mode 100644
index 0000000..3a4398c
--- /dev/null
+++ b/Tut2_4.cpp
@@ -0,0 +1,57 @@
+#include <iostream>
+using namespace std;
+struct node
+{
+	int data;
+	node* next = NULL;
+};
+void printAll(node* head)
+{
+	if (head != NULL)
+	{
+		cout << head->data << endl;
+		printAll(head->next);
+	}
+}
+void fun2(node* head)
+{
+	if (head == NULL)
+		return;
+	printf("%d ", head->data);
+	if (head->next != NULL)
+		fun2(head->next->next);
+	printf("%d ", head->data);
+}
+int main()
+{
+	node *a, *b, *c, *d, *e, *f, *g;
+	node *head;
+	g = new node();
+	g->data = 17;
+	g->next = NULL;
+	f = new node();
+	f->data = 5;
+	f->next = g;
+	e = new node();
+	e->data = 13;
+	e->next = f;
+	d = new node();
+	d->data = 6;
+	d->next = e;
+	c = new node();
+	c->data = 3;
+	c->next = d;
+	b = new node();
+	b->data = 5;
+	b->next = c;
+	a = new node();
+	a->data = -11;
+	a->next = b;
+	head = new node();
+	head->next = a;
+	//printAll(head);
+	fun2(c);
+	//printAll(head);
+	system("pause");
+	return 0;
+}
\ No newline at end of file
diff --git a/Tut2_5.cpp b/Tut2_5.cpp
new file mode 100644
index 0000000..6f0959d
--- /dev/null
+++ b/Tut2_5.cpp
@@ -0,0 +1,71 @@
+#include <iostream>
+using namespace std;
+struct node
+{
+	int data;
+	node* next = NULL;
+};
+void printAll(node* head)
+{
+	if (head != NULL)
+	{
+		cout << head->data << " ";
+		printAll(head->next);
+	}
+}
+void printAll2(node* head)
+{
+	if (head == NULL)
+	{
+		return;
+	}
+	node* temp = head;
+	do
+	{
+		cout << temp->data << " ";
+		temp = temp->next;
+	} while (temp != head);
+}
+void func1(node* head) {
+	node* temp = head;
+	while (temp != NULL) {
+		if (temp->next == NULL) {
+			temp->next = head;
+			return;
+		}
+		temp = temp->next;
+	}
+}
+int main()
+{
+	node *a, *b, *c, *d, *e, *f, *g;
+	node *head;
+	g = new node();
+	g->data = 7;
+	g->next = NULL;
+	f = new node();
+	f->data = 2;
+	f->next = g;
+	e = new node();
+	e->data = 100;
+	e->next = f;
+	d = new node();
+	d->data = 3;
+	d->next = e;
+	c = new node();
+	c->data = 9;
+	c->next = d;
+	b = new node();
+	b->data = 5;
+	b->next = c;
+	a = new node();
+	a->data = -11;
+	a->next = b;
+	head = new node();
+	head->next = a;
+	printAll(head);
+	func1(head);
+	printAll2(NULL);
+	system("pause");
+	return 0;
+}
\ No newline at end of file
diff --git a/Tut2_6.cpp b/Tut2_6.cpp
new file mode 100644
index 0000000..5607be4
--- /dev/null
+++ b/Tut2_6.cpp
@@ -0,0 +1,82 @@
+#include <iostream>
+using namespace std;
+struct node {
+	int data;
+	node *next = NULL;
+};
+node* deleteNth(node* head, int n)
+{
+	if (head == NULL || n < 0)
+	{
+		return head;
+	}
+	if (n == 0)
+	{
+		node *temp = head;
+		head = head->next;
+		delete temp;
+	}
+	else
+	{
+		node *pre = head, *cur = head->next;
+		for (int i = 1; i < n; i++)
+		{
+			pre = cur;
+			cur = cur->next;
+			if (cur == NULL)
+			{
+				break;
+			}
+		}
+		if (cur != NULL)
+		{
+			pre->next = cur->next;
+			delete cur;
+			cur = NULL;
+		}
+	}
+	return head;
+}
+void printAll(node* head)
+{
+	if (head != NULL)
+	{
+		cout << head->data << " ";
+		printAll(head->next);
+	}
+}
+int main()
+{
+	node *a, *b, *c, *d, *e, *f, *g;
+	node *head;
+	g = new node();
+	g->data = 7;
+	g->next = NULL;
+	f = new node();
+	f->data = 2;
+	f->next = g;
+	e = new node();
+	e->data = 100;
+	e->next = f;
+	d = new node();
+	d->data = 3;
+	d->next = e;
+	c = new node();
+	c->data = 9;
+	c->next = d;
+	b = new node();
+	b->data = 5;
+	b->next = c;
+	a = new node();
+	a->data = -11;
+	a->next = b;
+	head = new node();
+	//head->data = 0;
+	head->next = a;
+	printAll(head);
+	cout << endl;
+	head = deleteNth(head, 7);
+	printAll(head);
+	system("pause");
+	return 0;
+}
\ No newline at end of file
diff --git a/Tut2_Ex.cpp b/Tut2_Ex.cpp
new file mode 100644
index 0000000..34500a9
--- /dev/null
+++ b/Tut2_Ex.cpp
@@ -0,0 +1,94 @@
+/*
+Write a function:
+1. Append a node to linked list.
+2. Prepend a node to linked list.
+3. Search and return pointer to node if existed otherwise, return NULL.
+*/
+#include <iostream>
+using namespace std;
+struct node
+{
+	int data;
+	node* next;
+};
+void appendList(node* &head, int data)
+{
+	node* newNode = new node;
+	newNode->data = data;
+	newNode->next = NULL;
+	if (head == NULL)
+	{
+		head = newNode;
+		return;
+	}
+	node* temp = head;
+	while (temp->next != NULL)
+	{
+		temp = temp->next;
+	}
+	temp->next = newNode;
+}
+void prependList(node* &head, int data)
+{
+	node* newNode = new node;
+	newNode->data = data;
+	if (head == NULL)
+	{
+		newNode->next = NULL;
+		head = newNode;
+		return;
+	}
+	newNode->next = head;
+	head = newNode;
+}
+node* searchNode(node* head, int val)
+{
+	node* temp = head;
+	while (temp != NULL)
+	{
+		if (temp->data == val)
+		{
+			return temp;
+		}
+		temp = temp->next;
+	}
+	return NULL;
+}
+node* searchLastNode(node* head, int val)
+{
+	node* temp = head;
+	node* pos = NULL;
+	while (temp != NULL)
+	{
+		if (temp->data == val)
+		{
+			pos = temp;
+		}
+		temp = temp->next;
+	}
+	return pos;
+}
+void printAll(node* head)
+{
+	if (head != NULL)
+	{
+		cout << head->data << " ";
+		printAll(head->next);
+	}
+}
+int main()
+{
+	node* head = NULL;
+	for (int i = 0; i < 10; i++)
+	{
+		prependList(head, i);
+	}
+	for (int i = 0; i < 10; i++)
+	{
+		prependList(head, i);
+	}
+	cout << searchLastNode(head, 8);
+	printAll(head);
+	system("pause");
+	return 0;
+}
\ No newline at end of file
diff --git a/Tut3.cpp b/Tut3.cpp
new file mode 100644
index 0000000..12a78f4
--- /dev/null
+++ b/Tut3.cpp
@@ -0,0 +1,139 @@
+#include <iostream>
+
+using namespace std;
+
+struct Node
+{
+	int data;
+	Node *next;
+};
+
+void appendList(Node* &head, int data)
+{
+	Node* newNode = new Node;
+	newNode->data = data;
+	newNode->next = NULL;
+	if (head == NULL)
+	{
+		head = newNode;
+		return;
+	}
+	Node* temp = head;
+	while (temp->next != NULL)
+	{
+		temp = temp->next;
+	}
+	temp->next = newNode;
+}
+
+void makeCircularLinkedList(Node* head) {
+	Node* temp = head;
+	while (temp != NULL) {
+		if (temp->next == NULL) {
+			temp->next = head;
+			return;
+		}
+		temp = temp->next;
+	}
+}
+
+void printSingleLinkedList(Node* head)
+{
+	if (head != NULL)
+	{
+		cout << head->data << " ";
+		printSingleLinkedList(head->next);
+	}
+}
+
+void printCircularLinkedList(Node* head)
+{
+	if (head == NULL) return;
+	Node* temp = head;
+	do
+	{
+		cout << temp->data << " ";
+		temp = temp->next;
+	} while (temp != head);
+}
+
+void printList(Node* head)
+{
+	if (head == NULL) return;
+	Node *temp = head;
+	do
+	{
+		cout << temp->data << " ";
+		temp = temp->next;
+	} while (temp != NULL && temp != head);
+}
+
+Node* searchList(Node* head, int data)
+{
+	Node* temp = head;
+	while (temp != NULL)
+	{
+		if (temp->data == data)
+		{
+			return temp;
+		}
+		temp = temp->next;
+	}
+	return NULL;
+}
+
+Node* deleteNth(Node* head, int n)
+{
+	if (head == NULL || n < 0)
+	{
+		return head;
+	}
+	if (n == 0)
+	{
+		Node *temp = head;
+		head = head->next;
+		delete temp;
+	}
+	else
+	{
+		Node *pre = head, *cur = head->next;
+		for (int i = 1; i < n; i++)
+		{
+			pre = cur;
+			cur = cur->next;
+			if (cur == NULL)
+			{
+				break;
+			}
+		}
+		if (cur != NULL)
+		{
+			pre->next = cur->next;
+			delete cur;
+			cur = NULL;
+		}
+	}
+	return head;
+}
+
+int main()
+{
+	Node* head = NULL;
+	Node* search = NULL;
+	for (int i = 0; i < 10; ++i)
+	printSingleLinkedList(head);
+	cout << endl;
+	printList(head);
+	cout << endl;
+	search = searchList(head, 5);
+	cout << (void*)search << endl;
+	makeCircularLinkedList(head);
+	printCircularLinkedList(head);	{
+		appendList(head, i);
+	}
+	cout << endl;
+	printList(head);
+	cout << endl;
+	system("pause");
+	return 0;
+}
\ No newline at end of file