백준 8393

 

▶풀이방법

import java.util.*;

public class Main{
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		int num = sc.nextInt();
		int sum = 0;
		
		for(int i = 1; i <= num; i++) {
			sum += i;
		}
		
		System.out.println(sum);
	}
}