Hi,

Could you help me to covert this python code to C++? This code is working in python now. I want to learn that how to write C++ code. The purpose of this Python code is lexical analysis. Thank you so much!

Following is a simple test case

following is Python code:

from enum import Enum

import string

keyword = ['while', 'if', 'for', 'else', 'get', 'int', 'endif', 'return', 'put', 'function', 'real']

# %% checked later for separators

separator = ['(', ')', '[', ']', '{', '}', '!', ';', ',', ':']

class State(Enum):

REJECT = 0, 'REJECT'

INTEGER = 1, 'INTEGER'

REAL = 2, 'REAL'

OPERATOR = 3, 'OPERATOR'

SEPARATOR = 4, 'SEPARATOR'

IDENTIFIER = 5, 'IDENTIFIER'

KEYWORD = 6, 'KEYWORD'

UNKNOWN = 7, 'UNKNOWN'

SPACE = 8, 'SPACE'

def __new__(cls, value, name):

member = object.__new__(cls)

member._value_ = value

member.fullname = name

return member

def __int__(self):

return self.value

# still working on the states

stateTable = [

[0, State.INTEGER, State.REAL, State.OPERATOR, State.SEPARATOR, State.IDENTIFIER, State.KEYWORD, State.UNKNOWN, State.SPACE],

[State.INTEGER, State.INTEGER, State.REAL, State.REJECT, State.REJECT, State.IDENTIFIER, State.REJECT, State.REJECT, State.REJECT],

[State.REAL, State.REAL, State.UNKNOWN, State.REJECT, State.REJECT, State.REJECT, State.REJECT, State.REJECT, State.REJECT],

[State.OPERATOR, State.REJECT, State.REJECT, State.OPERATOR, State.REJECT, State.REJECT, State.REJECT, State.REJECT, State.REJECT],

[State.SEPARATOR, State.REJECT, State.REJECT, State.REJECT, State.REJECT, State.REJECT, State.REJECT, State.REJECT, State.REJECT],

[State.IDENTIFIER, State.IDENTIFIER, State.REJECT, State.REJECT, State.REJECT, State.IDENTIFIER, State.REJECT, State.REJECT, State.REJECT],

[State.KEYWORD, State.REJECT, State.REJECT, State.REJECT, State.REJECT, State.REJECT, State.REJECT, State.REJECT, State.REJECT],

[State.UNKNOWN, State.UNKNOWN, State.UNKNOWN, State.UNKNOWN, State.UNKNOWN, State.UNKNOWN, State.UNKNOWN, State.UNKNOWN, State.REJECT],

[State.SPACE, State.REJECT, State.REJECT, State.REJECT, State.REJECT, State.REJECT, State.REJECT, State.REJECT, State.REJECT],

]

def checkToken(token):

# print("Check Token", token)

if token.isdigit():

# print("is digit")

return State.INTEGER

elif token.isspace():

# print("is space")

return State.SPACE

elif token == '$':

return State.IDENTIFIER

elif token == '.':

# print("is real")

return State.REAL

for i in string.punctuation:

if token == i:

if token in separator:

# print("is separator")

return State.SEPARATOR

# print("is punc")

return State.OPERATOR

if token.isalpha():

# print("is alpha")

return State.IDENTIFIER

else:

# print("is unknown")

return State.UNKNOWN

comment = False

def Lexer(expression):

global col, comment

tokens = []

col = State.REJECT

currentState = State.REJECT

prevState = State.REJECT

currentToken = ""

for token in expression:

col = checkToken(token)

currentState = stateTable[int(currentState)][int(col)]

# print("currentToken is ", currentToken, "currentState is ", currentState.fullname)

if currentState == State.REJECT:

currentToken = currentToken.replace(" ", "")

if prevState != State.SPACE and currentToken:

if currentToken == '!':

if comment:

comment = False

else:

comment = True

elif not comment:

if currentToken in keyword:

tokens.append({'token': currentToken, 'lexeme': State.KEYWORD})

elif prevState == State.IDENTIFIER and currentToken.find('$') > -1 and currentToken[len(currentToken)-1] != '$':

tokens.append({'token': currentToken, 'lexeme': State.UNKNOWN})

elif currentToken == '%%':

tokens.append({'token': currentToken, 'lexeme': State.SEPARATOR})

else:

tokens.append({'token': currentToken, 'lexeme': prevState})

currentToken = token

currentState = checkToken(token)

else:

currentToken = currentToken.replace(" ", "")

currentToken += token

prevState = currentState

if currentState != State.SPACE and currentToken and currentState != State.REJECT:

tokens.append({'token': currentToken, 'lexeme': prevState})

return tokens

filename = raw_input('Enter a input filename: ')

results = []

with open(filename) as inputfile:

for line in inputfile:

results.append(Lexer(line))

# print("Token\t\t=\tLexeme")

# for val in results:

# for r in val:

# if r['lexeme'].fullname == 'REAL':

# print("%s \t\t=\t %s") % (r['lexeme'].fullname, r['token'])

# else:

# print("%s \t=\t %s") % (r['lexeme'].fullname, r['token'])

# include output file

filename = raw_input('Enter a output filename: ')

with open(filename, "w+") as outputfile:

print >> outputfile, "Token\t\t=\tLexeme"

for val in results:

for r in val:

if r['lexeme'].fullname == 'REAL':

print >> outputfile, ("%s \t\t=\t %s") % (r['lexeme'].fullname, r['token'])

else:

print >> outputfile, ("%s \t=\t %s") % (r['lexeme'].fullname, r['token'])