Calculator in python

def add(a,b):
    c=a+b
    return(c)
    
d=add(3,4)
print(d)

def changelist(mylist):
    mylist.extend([1,2,3,4])
    return mylist

mylist=[10,20,30]
print("values inside before function call:",mylist)
changelist(mylist)
print("values after function call:",mylist)

def printinfo(name,age):
    print("Name:",name)
    print("Age",age)
    return

#now calling printinfofunction
printinfo(age=50,name="mikki")
printinfo(10,"mikki")
'''default argument demo'''

"""def printinffo(name='john',age=35):
    print("Name:",name)print("Age", age)
    return
printinffo(age=50,name="mikki")
printinffo(name="harry")
printinffo()
printinfo    """

def printinnfo(arg1,*vartuple):
    print("output is:")
    print(arg1)
    print(sum(vartuple))
    print (vartuple)
    for var in vartuple:
        print(var)
    return

#now calling printinfo Function
printinnfo(10)
printinnfo(20,77,58,42,21,5)

def printinnfo(*vartuple):
  
    print(sum(vartuple))
    print (vartuple)
    for var in vartuple:
        print(var)
    return

#now calling printinfo Function
printinnfo(10)
printinnfo(20,77,58,42,21,5)



def add(x,y):
    return x+y

def sub(x,y):
    return x-y

def mul(x,y):
    return x*y

"""def div (x,y):
    return x/y

print("select option")
print("1.add")
print("2.sub")
print("3.mul")
print("4.div")

choice=input("enter choice(1/2/3/4):")

num1=int(input("enter first number:"))
num2=int(input("enter second number:"))

if choice=="1":
    print(num1,"+",num2,"=",add(num1,num2))
    
elif choice=="2":
    print(num1,"-",num2,"=",sub(num1,num2))
    
elif choice=="3":
     print(num1,"*",num2,"=",mul(num1,num2))
           
elif choice=="4":
     print(num1,"/",num2,"=",div(num1,num2))
     
else:
   print("invalid input:")"""
   
"""total=0
def sum(arg1,arg2):
    global total
    total=arg1+arg2
    print("inside the function:",total)
    return total
sum(20,30)
print("outside the function global total:",total)"""

def fact(n):
   if n=1:
        return 1
    else:
        return n*fact(n-1)
    
    a=int(input("enter a number:"))
    print(fact(a))
    
    
def factorial(n):
    for i in range(n):
        a=a*i
        a-=1
        return a
s=int(input("enter the number:"))
print(factorial(s))