#include <iostream>
#include <vector>
#include <algorithm>
std::ostream& operator<<(std::ostream& os, const std::vector<char> &v) {
int size = v.size();
for (int i = 0; i < size; i++) {
os << v.at(i) << " ";
}
return os;
}
int main()
{
std::vector<char> v = {'a', 'b', 'c', 'd', 'e'};
std::cout << v;
return 0;
}
/*
run:
a b c d e
*/