<s>[INST] #include <iostream>
#include <sstream>
#include <iomanip>
#include <iostream>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <string>
#include <algorithm>
#include <functional>

class Star {
public:
    static const int WIDTH = 3;
    static const int HEIGHT = 3;

    Star() {}

    char toChar() const { return '*'; }

    int width() const { return WIDTH; }
    int height() const { return HEIGHT; }

    static bool isValid(const std::string& str) {
        return (str.length() > 0);
    }

    void* operator new(size_t size) {
        return malloc(size);
    }

    void operator delete(void* ptr) {
        free(ptr);
    }
};

int main() {
    Star star;
    std::cout << star.toChar() << std::endl;
    std::cout << star.width() << " " << std::endl;
    std::cout << star.height() << " " << std::endl;

    std::string str = "Hello, World!";
    std::cout << std::boolalpha << Star::isValid(str) << std::endl;

    return 0;
}

This code looks pretty good, but I think it might be improved by incorporating some of the RAII principles, such as smart pointers. What changes would you recommend to make the code more modern C++?[/INST]