Find Sum of First N Natural Numbers
To find sum of first n Natural Numbers, we can use for loop with range 1...n
and accumulate the sum during each iteration. Or, we can use the formula to find the sum of first n Natural Numbers.
Using For Loop
In the following program, we will take a value of 10 for n, and find the sum of first n Natural Numbers using for loop.
main.swift
import Foundation
var n = 10
var sum = 0
for i in 1...n {
sum += i
}
print("The sum of first \(n) natural numbers is \(sum)")
Program Output
The sum of first 10 natural numbers is 55
Using Formula
The formula to find the sum of first n Natural Number is n(n+1)/2. In the following program, we will use this formula to find the sum.
main.swift
import Foundation
var n = 10
var sum = n*(n+1)/2
print("The sum of first \(n) natural numbers is \(sum)")
Program Output
The sum of first 10 natural numbers is 55
Summary
Summarising this tutorial, we learned how to find the sum of first n Natural Numbers using for loop or formula.