C Program to thread the tree in post order?

Answer 1

I'm not giving you a full, ready-to-run code, just a skeleton program that may give you some ideas to start with. (And this way you will learn more.)

Let's suppose your tree elements look like this:

TreeElement{
integer data;
pointer leftnode, rightnode;
}

Then this is the frame of the program:

TreeWalk(TreeElement){
if(exists(leftnode)){ TreeWalk(leftnode); } //if there is a left subtree from this TreeElement, then traverse that
if(exists(rightnode)){ TreeWalk(rightnode); } //same for the right side
process(data); //do whatever you need to do
}

So this is the idea behind the postorder tree traversal, the actual details are up to you and the concrete problem.