Title: Design prioritized operators algorithm parse

Requirements

Using C/C++/java language design a prioritized operators parser. The prioritized operators analysis method is used to design an analysis and interpretation program, which performs lexical analysis, syntax analysis and expression evaluation on the input assignment statement, output statement and clear statement, and stores them in the specified variables; If there is an error, you will be prompted with error related information.

Example:

Grammar

S v=E | E? | clear

E E+T | ET | T

T T*F | T/F | F

F (E) | v | c

Analysis

FIRSTVT(S) = { v , ? , clear } LASTVT(S) = { ? , clear }

FIRSTVT(F) = { ( , v , c } LASTVT(F) = { ) , v , c }

FIRSTVT(T) = {* , / , ( , v , c } LASTVT(T) = {* , / , ) , v , c }

FIRSTVT(E) = {+ , - , * , / , ( , v , c} LASTVT(E) = {+ , - , * , / , } , v , c}

SOurce Code:

Token: + - r * 1 6 ( 7 ) 8 4 5 9 10 1 clear 11 ? 2 # 12 3 N 13 Priority relation table: = ? ) clear N + > > > > > > > * > > > > > > > > > > > > > V > > > > > > > > > clear # N > > > > > > > * > > > > > > > > > > > > > V > > > > > > > > > clear # N