This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.

Terence hiu wrote:Say i have a tree structure created in java

root= +
root left node = +
rood right node = 4
root left of left =2
root left of right =3

(2+3)+4

how would i calculate this tree?

If I were to do it, I would choose to do it recursively. Encountering a number would be the base condition, where the number is simply returned. Encountering an operator will trigger two recursive calls to get the operands which will be needed to calculate the value to be returned.

Terence hiu wrote:Say i have a tree structure created in java

root= +
root left node = +
rood right node = 4
root left of left =2
root left of right =3

(2+3)+4

how would i calculate this tree?

If I were to do it, I would choose to do it recursively. Encountering a number would be the base condition, where the number is simply returned. Encountering an operator will trigger two recursive calls to get the operands which will be needed to calculate the value to be returned.