CODEWITHSUNDEEP
pythonpython-3.x
QQQQlanguage
QQQQlanguage

Reputation: 11

Summation with for loop in python

I input 10 to the below sequence, the it prints sum = 56 I list what sum includes, they are 1,2,3,4,5,6,7,8,9,10. I wonder what's wrong with the calculation of sum.

=======================================

n = int(input('input number?'))

sum = 1


for i in range(1,n+1,1):

     sum += i


print(sum)

Upvotes: 1

Views: 871

Answers (2)

Grigori Demin
Grigori Demin

Reputation: 19

I don't know why the variable 'sum' is initialized to 1. It should be 0. You will get the correct result. :)

Upvotes: 0

Daisuke Akagawa
Daisuke Akagawa

Reputation: 484

That's because you first define sum = 1. The true result is 55 but you increment it by yourself.

true code is below

n = int(input('input number?'))
result = sum(range(1, n+1))

You should not use sum as a variable name because sum is a built-in function. And in this case, you can calculate summantion by sum so easily.

Upvotes: 1

Related Questions