ex1.py

keywords = {"auto","break","case","char","const","continue","default","do",
"double","else","enum","extern","float","for","goto",
"if","int","long","register","return","short","signed",
"sizeof","static","struct","switch","typedef","union",
"unsigned","void","volatile","while","printf","scanf","%d","include","stdio.h","main"}

operators = {"+","-","*","/","<",">","=","<=",">=","==","!=","++","--","%"}

delimiters = {'(',')','{','}','[',']','"',"'",';','#',',',''}

def detect_keywords(text):
	arr = []
	for word in text:
		if word in keywords:
			arr.append(word)
	return list(set(arr))

def detect_operators(text):
	arr = []
	for word in text:
		if word in operators:
			arr.append(word)
	return list(set(arr))

def detect_delimiters(text):
	arr = []
	for word in text:
		if word in delimiters:
			arr.append(word)
	return list(set(arr))

def detect_num(text):
	arr = []
	for word in text:
		try:
			a = int(word)
			arr.append(word)
		except:
			pass
	return list(set(arr))
"""
this is original function for detecting identifier
def is_identifier(token):
    if token[0] in numbers or token in keywords:
        return False
    else:
        return identifier(token)

def identifier(token):
    if len(token)<2 and (token[0] in alphabets or token[0] in numbers or token[0] == "_"):
        return True
    elif token[0] in alphabets or token[0] in numbers or token[0] == "_":
        return identifier(token[1:])
    else:
        return False
"""
def detect_identifiers(text):
	k = detect_keywords(text)
	o = detect_operators(text)
	d = detect_delimiters(text)
	n = detect_num(text)
	not_ident = k + o + d + n
	arr = []
	for word in text:
		if word not in not_ident:
			arr.append(word)
	return arr

with open('e1-example.txt') as t:
	text = t.read().split()

print("Keywords: ",detect_keywords(text))
print("Operators: ",detect_operators(text))
print("Delimiters: ",detect_delimiters(text))
print("Identifiers: ",detect_identifiers(text))
print("Numbers: ",detect_num(text))