union.cpp

#include <algorithm> // std::set_union, std::sort
#include <iostream> // std::cout
#include <vector> // std::vector

// Driver code
int main()
{
	int first[] = { 5, 10, 15, 20, 25 };
	int second[] = { 50, 40, 30, 20, 10 };
	int n = sizeof(first) / sizeof(first[0]);

	// Print first array
	std::cout << "First array contains :";
	for (int i = 0; i < n; i++)
		std::cout << " " << first[i];
	std::cout << "\n";

	// Print second array
	std::cout << "Second array contains :";
	for (int i = 0; i < n; i++)
		std::cout << " " << second[i];
	std::cout << "\n\n";

	std::vector<int> v(10);
	std::vector<int>::iterator it, st;

	std::sort(first, first + n);
	std::sort(second, second + n);

	// Using default function
	it = std::set_union(first, first + n, second,
						second + n, v.begin());

	std::cout << "The union has " << (it - v.begin())
			<< " elements:\n";
	for (st = v.begin(); st != it; ++st)
		std::cout << ' ' << *st;
	std::cout << '\n';

	return 0;
}