#include <iostream>
using namespace std;

int main() {
    // បោះពុម្ពពាក្យ Hello World
    cout << "Hello, World!" << endl;
    return 0;
}

#include <iostream>
#include <string>
using namespace std;

int main() {
    // ប្រកាស Variable
    int age = 20;
    float height = 1.75;
    char grade = 'A';
    bool isStudent = true;
    string name = "សុខ វិចិត្រ";

    // Constant — តម្លៃមិនអាចផ្លាស់ប្តូរ
    const double PI = 3.14159265;

    cout << "ឈ្មោះ: " << name << endl;
    cout << "អាយុ: " << age << endl;
    cout << "កម្ពស់: " << height << " m" << endl;
    cout << "PI = " << PI << endl;

    return 0;
}

#include <iostream>
using namespace std;

int main() {
    int a = 10, b = 3;

    cout << "a + b = " << (a + b) << endl;  // 13
    cout << "a - b = " << (a - b) << endl;  // 7
    cout << "a * b = " << (a * b) << endl;  // 30
    cout << "a / b = " << (a / b) << endl;  // 3
    cout << "a % b = " << (a % b) << endl;  // 1

    // Comparison
    cout << "a > b: " << (a > b) << endl;   // 1 (true)
    cout << "a == b: " << (a == b) << endl; // 0 (false)

    return 0;
}

#include <iostream>
#include <string>
using namespace std;

int main() {
    int age;
    string name;

    cout << "សូមបញ្ចូលឈ្មោះ: ";
    getline(cin, name);  // ទទួលខ្សែអក្សរ (រួមទាំងដកឃ្លា)

    cout << "សូមបញ្ចូលអាយុ: ";
    cin >> age;

    cout << "------------------" << endl;
    cout << "ឈ្មោះ: " << name << endl;
    cout << "អាយុ: " << age << " ឆ្នាំ" << endl;

    return 0;
}

#include <iostream>
using namespace std;

int main() {
    int score;
    cout << "បញ្ចូលពិន្ទុ: ";
    cin >> score;

    // if / else if / else
    if (score >= 90) {
        cout << "ថ្នាក់ A - ល្អប្រសើរ!" << endl;
    } else if (score >= 80) {
        cout << "ថ្នាក់ B - ល្អ" << endl;
    } else if (score >= 70) {
        cout << "ថ្នាក់ C - មធ្យម" << endl;
    } else {
        cout << "ថ្នាក់ F - ត្រូវពិនិត្យម្តងទៀត" << endl;
    }

    // switch statement
    int day = 3;
    switch (day) {
        case 1: cout << "ថ្ងៃចន្ទ" << endl; break;
        case 2: cout << "ថ្ងៃអង្គារ" << endl; break;
        case 3: cout << "ថ្ងៃពុធ" << endl; break;
        default: cout << "ថ្ងៃផ្សេងទៀត" << endl;
    }

    return 0;
}

#include <iostream>
using namespace std;

int main() {
    // for loop
    cout << "=== for loop ===" << endl;
    for (int i = 1; i <= 5; i++) {
        cout << "i = " << i << endl;
    }

    // while loop
    cout << "=== while loop ===" << endl;
    int n = 1;
    while (n <= 5) {
        cout << "n = " << n << endl;
        n++;
    }

    // do-while loop
    cout << "=== do-while ===" << endl;
    int x = 1;
    do {
        cout << "x = " << x << endl;
        x++;
    } while (x <= 3);

    // break and continue
    for (int j = 0; j < 10; j++) {
        if (j == 3) continue; // រំលងលេខ 3
        if (j == 6) break;    // ឈប់នៅ 6
        cout << j << " ";
    }
    cout << endl;

    return 0;
}

#include <iostream>
using namespace std;

// Function ដែល return តម្លៃ
int add(int a, int b) {
    return a + b;
}

// Function ដែលមិន return (void)
void greet(string name) {
    cout << "សួស្តី, " << name << "!" << endl;
}

// Function Overloading (ឈ្មោះដូចគ្នា Parameters ខុសគ្នា)
double multiply(double a, double b) { return a * b; }
int    multiply(int a, int b)       { return a * b; }

// Default Parameters
void showInfo(string name, int age = 18) {
    cout << name << " | អាយុ: " << age << endl;
}

int main() {
    cout << add(5, 3) << endl;    // 8
    greet("វណ្ណា");
    cout << multiply(2.5, 4.0) << endl; // 10.0
    showInfo("សុភា");           // age=18 (default)
    showInfo("វិចិត្រ", 25);
    return 0;
}

#include <iostream>
#include <string>
using namespace std;

int main() {
    // 1D Array
    int scores[5] = {85, 92, 78, 95, 88};
    
    // Loop តាម Array
    int sum = 0;
    for (int i = 0; i < 5; i++) {
        sum += scores[i];
    }
    cout << "មធ្យម: " << (sum / 5.0) << endl;

    // 2D Array (Matrix)
   

int matrix[2][3] = {{1,2,3}, {4,5,6}};


    for (int r = 0; r < 2; r++) {
        for (int c = 0; c < 3; c++) {
            cout << matrix[r][c] << " ";
        }
        cout << endl;
    }

    // String operations
    string s = "Hello C++";
    cout << "ប្រវែង: " << s.length() << endl;
    cout << "Upper: " << s.substr(0, 5) << endl;

    return 0;
}

#include <iostream>
using namespace std;

int main() {
    int x = 42;
    int* ptr = &x;  // ptr ចង្អុល Address នៃ x

    cout << "តម្លៃ x: "   << x    << endl;  // 42
    cout << "Address x: " << &x   << endl;  // 0x......
    cout << "ptr ចង្អុល: " << ptr  << endl;  // Address (ដូចគ្នា)
    cout << "*ptr = "     << *ptr << endl;  // 42 (Dereference)

    // Dynamic Memory Allocation
    int* arr = new int[5];  // ជួលអង្គចាំ
    for (int i = 0; i < 5; i++) arr[i] = i * 10;
    for (int i = 0; i < 5; i++) cout << arr[i] << " ";
    cout << endl;
    
    delete[] arr;  // ត្រូតែ Free Memory!

    return 0;
}

#include <iostream>
#include <string>
using namespace std;

// ប្រកាស Struct
struct Student {
    string name;
    int    age;
    float  gpa;
};

void printStudent(Student s) {
    cout << "ឈ្មោះ: " << s.name 
         << " | អាយុ: " << s.age
         << " | GPA: " << s.gpa << endl;
}

int main() {
    Student s1 = {"វណ្ណា", 20, 3.8};
    Student s2 = {"សុភា", 22, 3.5};
    
    printStudent(s1);
    printStudent(s2);

    // Array of Structs
    Student students[3] = {
        {"ដារ៉ា",   19, 3.9},
        {"ចន្ទារ", 21, 3.2},
        {"ពិសី",   20, 3.7}
    };

    for (int i = 0; i < 3; i++) printStudent(students[i]);

    return 0;
}

#include <iostream>
#include <string>
using namespace std;

class BankAccount {
private:   // ចូលពីខាងក្រៅមិនបាន
    string owner;
    double balance;

public:    // ចូលពីខាងក្រៅបាន
    // Constructor
    BankAccount(string name, double initial) {
        owner   = name;
        balance = initial;
    }

    void deposit(double amount) {
        balance += amount;
        cout << "ដាក់ប្រាក់: $" << amount << endl;
    }

    void withdraw(double amount) {
        if (amount > balance) {
            cout << "ប្រាក់មិនគ្រប់គ្រាន់!" << endl;
        } else {
            balance -= amount;
            cout << "ដក: $" << amount << endl;
        }
    }

    void showBalance() {
        cout << owner << " | ប្រាក់: $" << balance << endl;
    }
};

int main() {
    BankAccount acc("វណ្ណា", 1000.0);
    acc.deposit(500);
    acc.withdraw(200);
    acc.showBalance();
    return 0;
}

#include <iostream>
using namespace std;

// Base Class (Parent)
class Animal {
public:
    string name;
    Animal(string n) : name(n) {}
    
    virtual void speak() {  // virtual = Polymorphism
        cout << name << ": ...\n";
    }
};

// Derived Class (Child)
class Dog : public Animal {
public:
    Dog(string n) : Animal(n) {}
    void speak() override {
        cout << name << ": វូហ្វវូ!\n";
    }
};

class Cat : public Animal {
public:
    Cat(string n) : Animal(n) {}
    void speak() override {
        cout << name << ": ម្យាវវ!\n";
    }
};

int main() {
    Animal* animals[] = {
        new Dog("បូ"),
        new Cat("មៀវ"),
        new Dog("រ៉ិចឆ្ហី")
    };

    for (auto a : animals) a->speak();  // Polymorphism!

    return 0;
}

#include <iostream>
using namespace std;

// Function Template — ប្រើជាមួយ Type ណាក៏បាន
template<typename T>
T maxVal(T a, T b) {
    return (a > b) ? a : b;
}

// Class Template
template<typename T>
class Box {
private:
    T value;
public:
    Box(T v) : value(v) {}
    void show() { cout << "Box: " << value << endl; }
};

int main() {
    cout << maxVal(3, 7)          << endl; // 7 (int)
    cout << maxVal(3.5, 2.1)     << endl; // 3.5 (double)
    cout << maxVal('z', 'a')    << endl; // z (char)

    Box<int>    intBox(42);
    Box<string> strBox("Hello");
    intBox.show();
    strBox.show();

    return 0;
}

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

int main() {
    // VECTOR — Dynamic Array
    vector<int> v = {5, 2, 8, 1, 9};
    v.push_back(4);        // បន្ថែមនៅខាងចុង
    sort(v.begin(), v.end()); // Sort ចំនួន
    
    cout << "Vector: ";
    for (auto n : v) cout << n << " ";
    cout << endl;  // 1 2 4 5 8 9

    // MAP — Key-Value Pairs
    map<string, int> scores;
    scores["វណ្ណា"] = 95;
    scores["សុភា"] = 87;
    scores["ដារ៉ា"] = 92;

    cout << "-- ពិន្ទុ --" << endl;
    for (auto& p : scores) {
        cout << p.first << ": " << p.second << endl;
    }

    // Algorithm
    auto it = max_element(v.begin(), v.end());
    cout << "ធំបំផុត: " << *it << endl;

    return 0;
}

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

int main() {
    // ===== សរសេរ File =====
    ofstream outFile("students.txt");
    if (outFile.is_open()) {
        outFile << "វណ្ណា 95\n";
        outFile << "សុភា 87\n";
        outFile << "ដារ៉ា 92\n";
        outFile.close();
        cout << "សរសេរ File បានជោគជ័យ!" << endl;
    }

    // ===== អាន File =====
    ifstream inFile("students.txt");
    string line;
    cout << "=== មាតិកា File ===" << endl;
    while (getline(inFile, line)) {
        cout << line << endl;
    }
    inFile.close();

    return 0;
}

#include <iostream>
#include <stdexcept>
using namespace std;

double divide(double a, double b) {
    if (b == 0) {
        throw invalid_argument("មិនអាចចែកនឹង 0 បាន!");
    }
    return a / b;
}

int main() {
    // try-catch Block
    try {
        cout << divide(10, 2) << endl;  // 5
        cout << divide(10, 0) << endl;  // Error!
    }
    catch (const invalid_argument& e) {
        cout << "Error: " << e.what() << endl;
    }
    catch (...) {
        cout << "Error មិនស្គាល់!" << endl;
    }

    // Multiple exceptions
    try {
        vector<int> v = {1, 2, 3};
        cout << v.at(10) << endl;  // Out of range!
    }
    catch (const out_of_range& e) {
        cout << "Out of range: " << e.what() << endl;
    }

    cout << "Program បន្តដំណើរការ..." << endl;
    return 0;
}