class tree {
public:
    tree() = default;
    tree(int base, const std::string &newCont = "*") { makeTree(base, newCont); }
    friend std::ostream &output(tree &oTree, std::ostream &os);
    void makeTree(int, const std::string&);
private:
    std::vector<std::string> Tree;
};

void tree::makeTree(int newBase, const std::string &newCont = "*") {
    Tree.clear();
    std::string tempString;
    for(int tempbase = 0; tempbase != newBase; ++tempbase) {
        tempString += newCont;
        Tree.push_back(tempString);
    }
}

std::ostream &output(tree &oTree, std::ostream &os) {
    for (auto c: oTree.Tree) {
        os << c << '\n';
    }
    return os;
}