Generate Random Strings in C++

#include <iostream>
#include <string>
#include <random>

const std::string ALPHANUMERIC =
    "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
const std::string HEX_CHARS = "0123456789abcdef";

std::string generateRandomString(int length, const std::string& customChars = ALPHANUMERIC) {
    std::random_device rd;
    std::mt19937 gen(rd());
    std::uniform_int_distribution<> distrib(0, customChars.length() - 1);

    std::string result;
    result.reserve(length);

    for (int i = 0; i < length; ++i) {
        result += customChars[distrib(gen)];
    }

    return result;
}

int main() {
    // Generate a 16-character alphanumeric string
    std::string randomString = generateRandomString(16);
    std::cout << randomString << std::endl;  // Example: aB3xY7mN2pQ9zR5t

    // Generate a 12-character hex string
    std::string hexString = generateRandomString(12, HEX_CHARS);
    std::cout << hexString << std::endl;  // Example: a3f7b2e9c4d1

    // Generate a 10-character lowercase string
    std::string lowercaseString = generateRandomString(10, "abcdefghijklmnopqrstuvwxyz");
    std::cout << lowercaseString << std::endl;  // Example: xmkpqrstuv

    return 0;
}