The following code example is taken from the book
C++23 - The Complete Guide
by Nicolai M. Josuttis,
Leanpub, 2026
The code is licensed under a
Creative Commons Attribution 4.0 International License.
// raw code
#include <iostream>
#include <random>
#include <generator>
#include <ranges>
// coroutine that generates random values:
std::generator<int> generateRandom()
{
// init random number generator with random initial state:
std::default_random_engine engine{std::random_device{}()};
// init a distribution of values from 1 to 100:
std::uniform_int_distribution<int> intDist{1, 100};
// yield endless sequence of random values between 1 and 100:
while (true) {
co_yield intDist(engine); // SUSPEND the coroutine with the next generated value
}
}
int main()
{
// iterate over the first 20 values generated by the coroutine view generateRandom():
for (const auto& val : generateRandom() | std::views::take(20)) {
std::cout << val << ' ';
}
std::cout << '\n';
}