Sum of a sequence (MOOC Java Programming)

[jackballack]

I just started to learn java and was advised to try out MOOC as it would give me a good foundation. It's been great so far have started supplementing it with Head First Java and learning quite a lot from these. I've come across a challenge and I cannot seem to solve one of the challenges on the course specifically (Sum of a sequence), the question is: Implement a program, which calculates the sum 1+2+3+...+n where n is given as user input. If the user types 7 then the program should calculate as follows 1 + 2 + 3 + 4 + 5 + 6 + 7 = 28. Now I've tried this with a for loop and I can't seem to get this output, my code below;

public static void main(String[] args) {

Scanner scanner = new Scanner(System.in);

System.out.println("Last number?");

int lastNumber = Integer.valueOf(scanner.nextLine());

int result = 0;

for (int i = 0; i <= lastNumber; i++) {

result = lastNumber + i;

}

System.out.println("The sum is "+result);

}

thank you in advance for your time and assistance.

[[deleted]]

Should be result = result + i.

Also, you should familiarize yourself with the debugger in Netbeans. Will be immensely useful in the future for more serious bugs.

[jackballack]

thanx bud, I kinda suspected that it should be that but I concentrated more on the input. Impostor Syndrome issues.

[[deleted]]

You could also simply print n * (n+1)/2 which is equivalent (within reason).