sum of 1 to 100 number

Java program for sum of 1 to 100 number without using for loop :


Let say we want to find sum of number for 1 to n number.

Formula :   sum = n * (n+1) / 2

Sum of number without using for loop

class SumOfNumber {


 public static void main(String[] args) {

  int sumUpTo = 100;

  int sum = sumUpTo * (sumUpTo + 1) / 2;

  System.out.println("Sum : " + sum);

 }

}

Output : 5050

Sum of 1 to 100 number using for loop : 

Sum of number using for loop

public class SumOfNumber {

 public static void main(String[] args) {

  int sumUpTo = 100;

  int sum = 0;

  for (int i = 1; i <= sumUpTo; i++) {

                     sum += i; // sum = sum + i;

  }

  System.out.println("sum = " + sum);

 }

}

Output : 5050