def infix_to_postfix(infix_expr):
precedence = {}
precedence["*"] = 3
precedence["/"] = 3
precedence["+"] = 2
precedence["-"] = 2
precedence["("] = 1
op_stack = Stack()
postfix_list = []
token_list = infix_expr.split()
for token in token_list:
if token in "ABCDEFGHIJKLLMNOPQRSTUVWXYZ" or token in "0123456789":
postfix_list.append(token)
elif token == '(':
op_stack.push(token)
elif token == ')':
top_token = op_stack.pop()
while top_token != '(':
postfix_list.append(top_token)
top_token = op_stack.pop()
else:
while (not op_stack.is_empty()) and (precedence[op_stack.peek()] >= precedence[token]):
postfix_list.append(op_stack.pop())
op_stack.push(token)
while not op_stack.is_empty():
postfix_list.append(op_stack.pop())
return "".join(postfix_list)
def par_checker(symbol_string):
s = Stack()
balanced = True
index = 0
while index < len(symbol_string) and balanced:
symbol = symbol_string[index]
if symbol in '([{':
s.push(symbol)
else:
if s.is_empty():
balanced = False
else:
top = s.pop()
if not matches(top, symbol):
balanced = False
index += 1
return balanced and s.is_empty()
def par_checker(symbol_string):
s = Stack()
balanced = True
index = 0
while index < len(symbol_string) and balanced:
symbol = symbol_string[index]
if symbol == '(':
s.push(symbol)
else:
if s.is_empty():
balanced = False
else:
s.pop()
index += 1
return balanced and s.is_empty()
def divide_by_2(dec_number):
rem_stack = Stack()
while dec_number > 0:
rem = dec_number % 2
rem_stack.push(rem)
dec_number //= 2 # // integer division
bin_string = ""
while not rem_stack.is_empty():
bin_string += str(rem_stack.pop())
return bin_string
def base_converter(dec_number, base):
rem_stack = Stack()
while dec_number > 0:
rem = dec_number % base
rem_stack.push(rem)
dec_number //= base # // integer division
base_string = ""
while not rem_stack.is_empty():
base_string += str(rem_stack.pop())
return base_string