Introduction - If you have any usage issues, please Google them yourself
Design a four-expression analysis software, which accepts four expressions from a file or keyboard input (support integer operands and variables), given expression in the form of a binary tree of the expression, and on the keyboard, press the subsequent traversal of the binary output.
For example, enter a+ b* c, output a b c*+
Note: Refer to the following design guidelines:
Recursive descent experimental design ideas and algorithm analysis
To construct each nonterminal U G a recursive process, it may be named as U. U generates right-hand side indicates the code structure of the process:
(1) If the end of the symbol, and lookaheads contrast, if the match is to advance a symbol otherwise error.
(2) If the non-terminal symbol, then call this nonterminal corresponding process. When there are multiple right part A of production, s