Pre, in, post order traversal of a binary tree.

Here's an example of traversing a binary tree in three different ways, pre-order, in-order, and post-order. I made the functions bracket the expressions so that they are easier to read. For instance, 2 * 4 + 5 * 6 is actually printed as ( (2 * 4) + (5 * 6) ).

This program is the first step in a little app I want to make that can convert infix notation (like 2 + (4 / (3+5)) - (4 + 4) ) into Scheme's pre-fix notation. (like: (- (+ 2 (/ 4 (+ 3 5))) (+ 4 4)) )

This program could then be used to help beginner Scheme programmers understand complicated arithmetic operations in pre-fix notation. The only thing I need to figure out is how Scheme handles string processing. If someone knows how to do this, could they point me in the right direction? I might just make a C++ front-end that accesses this code, which I also have to explore.

Please let me know if there are any ways that I can improve this code. Thanks.

Output:
(+ (* 2 3 )(* 4 5 ))
((2 * 3 )+ (4 * 5 ))
((2 3 * )(4 5 * )+ )

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Cinjection

Posted 87 Days Ago

Good point

closure

Posted 91 Days Ago

Hi, you might want to look at srfi-13 for string procedures. But why bother strings, when you can work on lists? :)

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Genetic Algorithm for solving the N-Queens problem
Converting from infix notation to prefix and postfix notation
Factoring numbers
Path Finding
Pre, in, post order traversal of a binary tree.

Splitting a list recursively in Scheme
Genetic Algorithm for solving the N-Queens problem
Converting from infix notation to prefix and postfix notation
Factoring numbers
Path Finding

Splitting a list recursively in Scheme
down the tree
Solving the N-Queens-Problem Part I
Factoring numbers
Filtered Accumulator