Just Run A Loop From 1 to N And Add All The Numbers Which Come In The Loop
And Also Dont Use Int Use long long BTW Your Approach Is Also Correct Code In C++
int main() {
// your code goes here
long long n;
cin>>n;
long long sum=(n*( n + 1 ))/2;
cout<<sum;
return 0;
}
Code In Java
import java.util.Scanner;
public class BitShifts {
public static void main(String[] args) {
Scanner scin = new Scanner(System.in);
long n = scin.nextInt();
System.out.println(n*(n+1)/2);
}
}