Sum of First N Natural Numbers

Easy ⏱ 8 min 88% acceptance ★★★★☆ 4.4
Write a function sum_naturals(n) that returns the sum 1 + 2 + ... + n using a for loop and an accumulator variable (do not use the closed-form formula).

Examples

Example 1
Input
sum_naturals(5)
Output
15
Explanation

1+2+3+4+5 = 15.

Example 2
Input
sum_naturals(1)
Output
1
Explanation

Just the single term 1.

Constraints

  • n is a positive integer.
  • Must use a loop, not the arithmetic series formula.

Topics

Loopsfor loopaccumulator

Companies

TCSInfosys

Hints

Hint 1

Start a `total = 0` accumulator before the loop.

Hint 2

Loop with `for i in range(1, n + 1):` and add i each time.

← Simple Command Parser (match-case) Factorial Using a Loop →
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