Question

I am making a java program that's supposed to store each solution in a variable and then use that variable when printing the results. I've figured out the other stuff (diameter of a circle, average of three numbers, etc. but can't figure out a quicker way to do the question below other than having a variable add every number. Would like a suggestion on how to do this. Thanks!

"The sum of a series of numbers from 1 to 100
(Hint: Is there a quicker way to do this than 1 + 2 + 3 + 4 + etc…)"

Answer 1

Method-1:

Source code:

import java.util.*;
public class Main
{
   public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        int n=100,sum=0;
        sum=n*(n+1)/2;
        /*There is a formula for first n numbers Sum
            sum=(n)*(n+1)/2
        */
        System.out.println("Sum of number 1-100:"+sum);
   }
}

Code screenshot:

OUTPUT:

Method-2

SourceCode:

import java.util.*;
public class Main
{
   public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        int n=100,sum=0,i=0;
  
        for (i=1;i<=n;i++)
        {
            sum=sum+i;
        }
        System.out.println("Sum of numbers 1-100:"+sum);
   }
}

Code Screenshot:

Output: