How to implement templates and generic programming features in C++?

#include <iostream>

// 模板函数的定义
template <typename T>
T Max(T a, T b) {
    return (a > b) ? a : b;
}

int main() {
    int num1 = 10;
    int num2 = 15;
    std::cout << "Max of " << num1 << " and " << num2 << " is: " << Max(num1, num2) << std::endl;

    double num3 = 3.14;
    double num4 = 2.71;
    std::cout << "Max of " << num3 << " and " << num4 << " is: " << Max(num3, num4) << std::endl;

    return 0;
}

#include <iostream>

// 模板类的定义
template <typename T>
class Stack {
private:
    T* data;  // 用于存储数据的数组
    int size;  // 栈的大小
    int top;  // 栈顶的索引

public:
    // 构造函数，对栈进行初始化
    Stack(int stackSize) {
        size = stackSize;
        data = new T[size];
        top = -1;
    }

    // 析构函数，释放内存
    ~Stack() {
        delete[] data;
    }

    // 入栈操作
    void Push(T val) {
        if (top == size - 1) {
            std::cout << "Stack is full!" << std::endl;
            return;
        }
        data[++top] = val;
    }

    // 出栈操作
    T Pop() {
        if (top == -1) {
            std::cout << "Stack is empty!" << std::endl;
            return T();
        }
        return data[top--];
    }

    // 获取栈顶元素
    T Top() {
        if (top == -1) {
            std::cout << "Stack is empty!" << std::endl;
            return T();
        }
        return data[top];
    }
};

int main() {
    Stack<int> intStack(3);
    intStack.Push(1);
    intStack.Push(2);
    intStack.Push(3);

    std::cout << "Top element: " << intStack.Top() << std::endl;
    std::cout << "Popped element: " << intStack.Pop() << std::endl;
    std::cout << "Popped element: " << intStack.Pop() << std::endl;
    std::cout << "Top element: " << intStack.Top() << std::endl;

    Stack<double> doubleStack(3);
    doubleStack.Push(1.23);
    doubleStack.Push(4.56);

    std::cout << "Top element: " << doubleStack.Top() << std::endl;
    std::cout << "Popped element: " << doubleStack.Pop() << std::endl;
    std::cout << "Top element: " << doubleStack.Top() << std::endl;

    return 0;
}

#include <iostream>
#include <vector>

// 快速排序的模板函数
template <typename T>
void QuickSort(std::vector<T>& arr, int left, int right) {
    if (left < right) {
        int i = left, j = right;
        T pivot = arr[left];

        while (i < j) {
            while (i < j && arr[j] > pivot) {
                j--;
            }
            if (i < j) {
                arr[i++] = arr[j];
            }

            while (i < j && arr[i] <= pivot) {
                i++;
            }
            if (i < j) {
                arr[j--] = arr[i];
            }
        }

        arr[i] = pivot;
        QuickSort(arr, left, i - 1);
        QuickSort(arr, i + 1, right);
    }
}

int main() {
    std::vector<int> arr {5, 2, 7, 1, 9, 3};
    QuickSort(arr, 0, arr.size() - 1);

    for (const auto& num : arr) {
        std::cout << num << " ";
    }
    std::cout << std::endl;

    return 0;
}