Indented Tree Printer

Build a class Node representing one node of a tree:
1. Node(const string& name) — a node with no children
2. void addChild(const Node& child) — stores a COPY of child in this node's list of children, keeping insertion order
3. void print(ostream& out, int depth = 0) const — writes depth times two spaces, then the node's name, then a newline; then calls print on each child with depth + 1

Write to out, not cout.

For a root root with children a and b, where a has one child a1, root.print(cout) prints the output shown in Expected Output.

solo.print(cout, 2) on a single node named solo prints 4 spaces and then solo.

Do NOT write a main function.