I don't know how to make my code work correctly

Question

I was practicing and I tried defining mathematical functions and other stuff, but then I got a bunch of errors and I ended up not having an error but the result was wrong. This is the code as of writing this:

def factorial(num):
 n = 1
    for i in range(1, num+1):
        n *= i
    return n

def series(start, end, expression):
    m = 0
    for n in range(start, end+1):
        m+=eval(expression)
    return m

ans1 = input("Do you want to use factorial or a series? ")
if ans1 == "Yes":
     ans2 = input("Series or factorial? ")
     if ans2 == "Series":
        start = int(input("Select the starting value of n. "))
        end = int(input("Select the final value of n. "))
        expression = input("Type the expression to be run in terms of n. ")
        m = series(start, end, expression)
        print("The result is: " + str(m))
     if ans2 == "Factorial":
        factorizing = int(input("Select the number to factorize. "))
        n = factorial(factorizing)
        print(n)
elif ans1 == "No":
     print("Ok!")

Thanks for the help, the factorial() is working perfectly now, but when in series i tried series(1, 5, 2*n+1), it gave me 35 when it was supposes to give 25, anyone know whats wrong?

Answer 1

You need to fix the logic. Such as start and end:

def factorial(num):
    n = 1
    for i in range(1, num + 1):
        n *= i
    return n


def series(start, end, expression):
    m = 0
    for n in range(start, end + 1):
        m += eval(expression)
    return m

ans1 = input("Do you want to use factorial or a series? Type `Yes` or `No`. ")
if ans1.lower() == "yes":
    ans2 = input("Series or factorial? ")
    if ans2.lower() == "series":
        start_end = input("Type start and end values, like `3 4`: ")
        start, end = start_end.split()
        start, end = int(start), int(end)
        if start > end:
            start, end = end, start
        expression = input("Type the expression to be run in terms of n: ")
        result = series(start, end, expression)
        print("The result is: " + str(result))
    elif ans2.lower() == "factorial":
        factorizing = int(input("Select the number to factorize: "))
        result = factorial(factorizing)
        print("The result is: " + str(result))
elif ans1.lower() == "no":
    print("Ok!")

Prints

Do you want to use factorial or a series? Type `Yes` or `No`. yes
Series or factorial? series
Type start and end values, like `3 4`: 10 5
Type the expression to be run in terms of n: 4
The result is: 24

For Factorial:

Do you want to use factorial or a series? Type `Yes` or `No`. yes
Series or factorial? factorial
Select the number to factorize: 5
The result is: 120

• Make sure your equations are correct.
• You can add details instructions so that all errors would be handled.