Java program to find sum of numbers from 1 to n

Hello CodeRanchers,
I am a beginner in Java.
I wrote a simple program to find the sum of numbers from 1 to n.
Please check my code and guide me if any improvement is needed.
Java Code
Copy code
Java
import java.util.Scanner;

public class SumOfNumbers {
   public static void main(String[] args) {

       Scanner sc = new Scanner(System.in);

       System.out.print("Enter a number: ");
       int n = sc.nextInt();

       int sum = 0;

       for (int i = 1; i <= n; i++) {
           sum = sum + i;
       }

       System.out.println("Sum from 1 to " + n + " is: " + sum);
   }
}
Explanation
We read the value of n from the user
We initialize sum as 0
Using a for loop, we add numbers from 1 to n
Finally, we print the result
Thanks in advance for your help 🙏
— Indira Kumar

Looks good to me. Nicely formatted too.

We do like you to UseCodeTags  (<---a link for you to read) here because it makes the code more readable.

A personal preference of mine would be to replace
sum = sum + i;
with
sum += i;

Slightly more succinct  but yours is fine.

And welcome to The Ranch.

Thank you very much for the feedback, Carey 🙂

I will start using code tags for better readability.
The suggestion to use `sum += i;` instead of `sum = sum + i;` makes sense and I’ll follow it.

Thanks again for the guidance!

Welcome to the Ranch again.

Work out what will happen if you enter a negative number as you run your program. Also what will happen if your argument is ≥2³⁰

That's a brute-force solution.

The tale is told about a young mathematician (I forget whom) who was tasked with the same problem as a way to keep him occupied for a while. He noted a certain property and returned the answer in under 5 minutes.

Hint: No looping is required.

There are two simple steps you can take yourself to get started:

1. Does the code compile correctly?

2. Does the code produce correct output when you run it and type in various values?

As Campbell suggests, there is more beyond that; your requirements don't mention that "n" must be greater than zero, for example, but they also don't say what should happen if a negative number is input.

Paul Clapham wrote:
As Campbell suggests, there is more beyond that; your requirements don't mention that "n" must be greater than zero, for example, but they also don't say what should happen if a negative number is input.

One of the first things taught in a Calculus course is the concept of domain and range. That is, what is allowed to go in and what is allowed to come out.

I consider that an essential part of the documentation of any software function, but alas, in the Real World, it is often not present. Of course, in addition to domain and range, proper documentation of a software function should also include exceptions and exception handling. What the function's invoker should do if the function fails/is presented with unacceptable data and what the function will do internally when an internal problem is discovered.

The Javadoc comment system is a good way to provide such documentation right alongside the code. I encourage its use. In fact, where reasonable, code samples I post here on the Ranch will include Javadoc comments.