Hello! I am trying to write an expression tree and I am currently having problems with using recursion and adding the nodes correctly. I am not sure how I am supposed to add the subtrees so that the operators and the operands are in the correct place, I'm also not entirely sure on how I'm supposed to stop. The input is in pre-fix(+34 as opposed to 3+4).
Any help would be good, I'm quite stuck on it!