팩토리얼의 덧셈 버전..?

Bash

read n
s=0
for ((i=1; i<=n; i++)); do
	((s += i))
done
echo $s

C

#include <stdio.h>

int main(void) {
	int n, s = 0;
	scanf("%d", &n);
	for (int i=1; i<=n; i++) {
		s+=i;
	}
	printf("%d\n", s);
	return 0;
}

Node.js

let n = Number(require("fs").readFileSync(0).toString().trim());
let s = 0;
while (0 < n) {
	s += n;
	n--;
}
console.log(s);

PHP

<?php
	fscanf(STDIN, "%d", $n);
	echo array_sum(range(1, $n));
?>

Python3

n = int(input())
print( sum(range(n+1)) )

Ruby

n = gets.chomp.to_i
puts (1..n).sum()