Introduction - If you have any usage issues, please Google them yourself
Realize the type of expression: one, an expression, and between a binary tree, there is a natural correspondence between. 2, assuming that the arithmetic expression Expression can contain variables (a ~ z), constant (0 ~ 9) and binary operators ( ,-,*,/,^)。 You realize the operation. (1) ReadExpr (E)- sequence of characters in the form of input grammar correct prefix expressions and tectonic expression of E. (2) WritrExpr (E)- used within parentheses express output infix expression E. (3) Assign (V, c)- realize the value V of the variables (V = c), variable initial value is 0. (4) Value (E)- on the arithmetic expression E is evaluated. (5) CompoundExpr (P, E1, E2)- Construction of a new composite expression (E1) P (E2).