Add variables using for loop In Java

Program:

package sum_project;
import java.util.Scanner;
public class summation {
public static void main(String[] args){
Scanner moni=new Scanner(System.in);
int userinput;
int sum=0;

System.out.println("Enter a number: ");
userinput=moni.nextInt();
if(userinput<0){
System.out.println("there are no number : ");
}
else{
for(int i=1;i<=userinput;i++){
sum=sum+i;
}
}
System.out.println("The sum is: "+sum);
}

}

Output:

Enter a number: 
20
The sum is: 210

Screenshot:

Program:

Output: