triples.cpp

#include <iostream>
#include <array>
#include <experimental/generator>
using namespace std::experimental;

using Triple = std::array<int, 3>;

// Generate infinite sequence of Pythagorean triples
generator<Triple> triples()
{
	for( int c = 2; true; c++ )
		for( int b = 2; b < c; b++ )
			for( int a = 2; a < b; a++ )
			{
				if( a * a + b * b == c * c )
					co_yield Triple{ a, b, c };
			}
}

// Take first `count` elements from the sequence
template<class E>
generator<E> take( generator<E> sequence, int count )
{
	int i = 0;
	for( auto e : sequence )
	{
		co_yield e;
		i++;
		if( i >= count )
			break;
	}
}

int main()
{
	for( auto t : take( triples(), 100 ) )
		std::cout << t[ 0 ] << ", " << t[ 1 ] << ", " << t[ 2 ] << std::endl;
}