编写语义分析程序，实现对算术表达式的类型检查和求值。要求所分析的算术表达式由如下文法产生：



E->E+T | E-T | T

T->T*F | T/F | F

F-> id | (E) | num

-Write semantic analysis procedures, to achieve the type checking and arithmetic expressions are evaluated. Requirements analysis arithmetic expressions generated by the following grammar: E->　E+T | ET | T T->　T* F | T/F | F F->　id | (E) | num