java stream sum() code example

Example 1: java running sum

public int[] runningSum(int[] nums) {
        
        int len = nums.length;
        
        for(int i = 1; i < len; i++){
            nums[i] += nums[i-1];
        }
        return nums;
    }

Example 2: sum of numbers in java

public class SumNatural {

    public static void main(String[] args) {

        int num = 100, sum = 0;

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

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