#include <iostream>
#include <unordered_set>
#include <string>
#include <random>
#include <sstream>
// A GUID (Globally Unique Identifier) and a UUID (Universally Unique Identifier)
// are essentially the same, both being 128-bit values used to uniquely identify
// information in computer systems.
// Generate a UUIDv4 (random)
std::string generate_uuid_v4() {
static std::random_device rd;
static std::mt19937_64 gen(rd());
static std::uniform_int_distribution<uint64_t> dist;
uint64_t part1 = dist(gen);
uint64_t part2 = dist(gen);
// Set version (4) and variant bits according to RFC 4122
part2 = (part2 & 0x3FFFFFFFFFFFFFFF) | 0x8000000000000000; // variant
part1 = (part1 & 0xFFFFFFFFFFFF0FFF) | 0x0000000000004000; // version 4
std::stringstream ss;
ss << std::hex;
ss << ((part1 >> 32) & 0xFFFFFFFF)
<< "-"
<< ((part1 >> 16) & 0xFFFF)
<< "-"
<< (part1 & 0xFFFF)
<< "-"
<< ((part2 >> 48) & 0xFFFF)
<< "-"
<< (part2 & 0xFFFFFFFFFFFF);
return ss.str();
}
int main() {
// Create a set containing three randomly generated UUIDs.
// generate_uuid_v4() produces a type‑4 GUID.
std::unordered_set<std::string> guids = {
generate_uuid_v4(),
generate_uuid_v4(),
generate_uuid_v4()
};
// Compute a hash value for the entire set.
// std::hash is idiomatic C++ for hashing values.
// We combine the hashes of all GUIDs in the set.
std::size_t hash = 0;
for (const auto& g : guids) {
hash ^= std::hash<std::string>{}(g) + 0x9e3779b97f4a7c15ULL + (hash << 6) + (hash >> 2);
}
// Print the GUIDs so we can see what was hashed.
std::cout << "GUIDs in the set:\n";
for (const auto& g : guids) {
std::cout << g << "\n";
}
// Print the resulting hash value.
std::cout << "\nHash of the GUID set: " << hash << "\n";
return 0;
}
/*
run:
GUIDs in the set:
261c0ca6-bb8e-47ec-9354-da3437db12cf
4c5dbb27-bd4b-46de-9941-8311de1dc6f6
d214f047-66c2-4a8e-b17e-23b426f7efef
Hash of the GUID set: 889325930297594684
*/
