Question

I have built a family tree program which thus far allows you to add relationships to nodes (mother, father, partner & siblings). This allows the tree to be built. well at least the links to be made.

My problem is I have to represent the tree textually. This is proving to be very hard. I thought of allowing to display the ancestors and descendants for a particular node but this proves to be difficult, especially when there are more than two generations for displaying ancestors (great grandparents and above).

To make things more clear I thought of using a file tree structure but got into a mess when displaying for great grandparents.

I can provide the source if anyone wants to see it.

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What I mean is using a file structure starts of with a pair of people:
e.g.

GRANDAD & GRANDMA
—DAD

——ME
——SISTER
—AUNT

——COUSIN
——COUSIN

This would be for showing my ancestors on my dads side (inclusive of me). My question is what happens if both my grandparents have parents? How would I represent such relationships with the above structure? I would have to show my great grand-parents but there would be two sets! One for my grandma and one for my grandad. The root has been split into two if you see what I mean….

I though about limiting the ‘show ancestors’ function to show only 2 generations above. Which means that a user can traverse through the tree and indentify his/her great grandparents by selecting their parent nodes and displaying their ancestors – but this seems laborious and not very intuitive.

Answer 1

The following method may do what you want. It will print a tree in a tabbed hierarchical structure:

public void printTree(Node root, int tabLevel, PrintStream out){
    for(int i =0;i < tabLevel; i++) out.print("\t");
    out.println(root)
    for(Node n: root.getChildren())
        printTree(n, tabLevel + 1, out);
}

You would call it like so:

printTree(rootNode, 0, System.out);

This doesn’t take into account all of the the complexities of a family tree, but it should provide a good place to start.