Country Generator for C++

Requires C++23 (e.g., -std=c++23 for GCC/Clang, /std:c++latest for MSVC).

API Reference · Usage Guide · Releases

Features

• Population-Weighted Generation. Countries are selected with probability proportional to their population, mirroring real-world demographics.

• Rich Country Data. Every generated country includes 31 fields: names, ISO codes, capital, region, coordinates, area, population, languages, currency, borders, timezones, driving side, demonyms, income level, and more.

• Region Filtering. Generate countries from a specific UN geoscheme region with get_country("Europe").

• Open Data Sources. Ships with two dataset tiers — full (~250 countries and territories) and lite (~195 sovereign states) — aggregated from mledoze/countries (ODbL), REST Countries, and World Bank.

• Deterministic Seeding. Per-call get_country(seed) for reproducible results, generator-level seed() / unseed() for deterministic sequences, and country::seed() for replaying a previous generation.

• Uniform Selection. Switch to equal-probability selection with weighted(false) — every country has the same chance regardless of population.

• Multi-Instance Support. Construct independent cntg instances with their own data and random engine — ideal for embedding inside other generators.

Integration

countrygen.hpp is the single required file released here. You also need random.hpp in the same directory. Add

#include <dasmig/countrygen.hpp>

// For convenience.
using cntg = dasmig::cntg;

to the files you want to generate countries and set the necessary switches to enable C++23 (e.g., -std=c++23 for GCC and Clang).

Additionally you must supply the country generator with the resources folder containing full/countries.tsv and/or lite/countries.tsv, also available in the release.

Usage

#include <dasmig/countrygen.hpp>
#include <iostream>

// For convenience.
using cntg = dasmig::cntg;

// Manually load a specific dataset tier if necessary.
cntg::instance().load(dasmig::dataset::lite);  // ~195 sovereign states
// OR
cntg::instance().load(dasmig::dataset::full);  // ~250 countries & territories

// Generate a random country (population-weighted).
auto country = cntg::instance().get_country();
std::cout << country.name_common << ", " << country.cca2
          << " (pop. " << country.population << ")" << '\n';

// Generate a country from a specific region.
auto eu = cntg::instance().get_country("Europe");

// Access all available fields.
std::cout << country.capital << '\n';
std::cout << country.languages << '\n';
std::cout << country.currency_name << " (" << country.currency_symbol << ")"
          << '\n';
std::cout << country.driving_side << '\n';
std::cout << country.income_level << '\n';

// Deterministic generation — same seed always produces the same country.
auto seeded = cntg::instance().get_country(42);

// Replay a previous country using its seed.
auto replay = cntg::instance().get_country(seeded.seed());

// Seed the engine for a deterministic sequence.
cntg::instance().seed(100);
// ... generate countries ...
cntg::instance().unseed(); // restore non-deterministic state

// Switch to uniform random selection (equal probability).
cntg::instance().weighted(false);
auto uniform = cntg::instance().get_country();
cntg::instance().weighted(true);

// Independent instance — separate data and random engine.
cntg my_gen;
my_gen.load("path/to/countries.tsv");
auto c = my_gen.get_country();

For the complete feature guide — fields, filtering, weighting, and more — see the Usage Guide.

Data

The country data is aggregated from multiple open-data sources:

Source	License	Contribution
mledoze/countries	ODbL v1.0	Names, ISO codes, borders, demonyms, languages, currencies
REST Countries	Open Source	Population, timezones, driving side, continents
World Bank	CC BY 4.0	Income level classification

See LICENSE_DATA.txt for details.

To regenerate datasets:

python scripts/prepare_countries.py            # generate both tiers
python scripts/prepare_countries.py --tier lite # lite only
python scripts/prepare_countries.py --tier full # full only

Related Libraries

Library	Description
name-generator	Culturally appropriate full names
nickname-generator	Gamer-style nicknames
birth-generator	Demographically plausible birthdays
biodata-generator	Procedural human physical characteristics
city-generator	Weighted city selection by population
entity-generator	ECS-based entity generation