Calculator.py

print('Operations performed here are addition(add), subtraction(sub), multiplication(mult), division(div), exponential(exp), factorial(fact)')

#Addition
def add():
    b=0
    num=int(input("Enter how many numbers you are adding : "))
    print("Enter the numbers : ")
    for i in range(num):
	    n=float(input())
	    b+=n
    print('Summation of the numbers is =',b)

#Subtraction
def sub():
	a=float(input('Enter 1st number : '))
	b=float(input('Enter 2nd number : '))
	print('Subtraction of the number is =',a-b)

#Multiplication
def mult():
    b=1
    num=int(input("Enter how many numbers you are multiplying : "))
    print("Enter the numbers : ")
    for i in range(num):
	    n=float(input())
	    b*=n
    print('Multiplication of the numbers is =',b)

#Division
def div():
	a=float(input('Enter Numerator : '))
	b=float(input('Enter Denominator : '))
	print('Exact division is =',a/b)
	print('Integral value of division is =',a//b)
	print('Remainder after division is =',a%b)

#Exponential
def exp():
	a=float(input('Enter Base : '))
	b=float(input('Enter Power : '))
	print('Exponential is given by =',a**b)

#Factorial
def fact():
    n=int(input('Enter a integer for its factorial: '))
    L=[]
    for i in range(n,0,-1):
        L.append(i)
    print('\nFactorial is also represented by:', ' * '.join(str(x) for x in L))
    def factorial(n):
        if n==0:
            return 1
        return n*factorial(n-1)
    print(f'\nFactorial of the number is = {n}! = {factorial(n)}')

#Defination ending
try:
	opt=input('\nAddition -> add\nSubtraction -> sub\nMultiplication -> mult\nDivision -> div\nPower -> exp\nFactorial ->fact\nEnter operator keyword you want to perform : ')
	while 1:
		if opt=='add':
			add()
		elif opt=='sub':
			sub()
		elif opt=='mult':
			mult()
		elif opt=='div':
			div()
		elif opt=='exp':
			exp()
		elif opt=='fact':
			fact()
		else:
			print('Enter correct operator keyword')
		opt_2=input('\nEnter an operator keyword again (enter 0 to stop) : ')
		if opt_2=='0':
			break
		opt=opt_2
except ValueError:
	print('Enter number or \'0\' only')