def calpostfix(stt):
stack = Stack()
for i in stt:
if i in '+-*/':
pop1 = stack.pop()
pop2 = stack.pop()
temp = pop2+i+pop1
stack.push(str(eval(temp)))
else:
stack.push(i)
print('calresult:',stack.peek())
def ToPostfix(expression):
L = []
stack = Stack()
for i in expression:
if i in '(+-*/':
stack.push(i)
elif i == ')':
while stack.peek() != '(':
L.append(stack.pop())
stack.pop()
else:
L.append(i)
print('postfix:',''.join(L))
return L
