Binary Expression Tree

Each internal node corresponds to the operator and each leaf node corresponds to the operand.

Example:

A expression tree for 3 * (5+7) would be:

      *
    /   \
   3     +
        / \
       5   7

prefix: (* 3 (+ 5 7)) -> mul(3, plus(5, 7))
infix: 3 * (5+7) -> 四則運算
postfix: 3 5 7 + * -> 電腦上實際想要執行運算的方式

Reference

• Wiki: Binary expression tree
• Expression Tree