#include <iostream>
#include <vector>

void Concatenate( std::vector<char>& string1, std::vector<char> string2 ) {
	string1.insert( string1.end(), string2.begin(), string2.end() );
}

int main() {
	std::vector<char> firstString;
	firstString.push_back('A');
	firstString.push_back('B');
	std::vector<char> secondString;
	secondString.push_back('X');
	secondString.push_back('Y');

	Concatenate( firstString, secondString );

	for( auto it = firstString.begin(); it != firstString.end(); ++it )
	{
		std::cout << (*it);
	}

	return 0;

}