Function print_tree_iterative 

pub fn print_tree_iterative(
    tree: &BTreeMap<String, Box<Tree>>,
    initial_depth: usize,
)

Prints the tree structure with indentation based on depth (ITERATIVE VERSION)

Uses an explicit stack to avoid recursion while keeping the order of print_tree.

Arguments

• tree - The tree to print
• initial_depth - Depth level of the first line for indentation