Java: Array with loop

Question

I need to create an array with 100 numbers (1-100) and then calculate how much it all will be (1+2+3+4+..+100 = sum).

I don't want to enter these numbers into the arrays manually, 100 spots would take a while and cost more code.

I'm thinking something like using variable++ till 100 and then calculate the sum of it all. Not sure how exactly it would be written. But it's in important that it's in arrays so I can also say later, "How much is array 55" and I can could easily see it.

Answer 1

Here's how:

// Create an array with room for 100 integers int[] nums = new int[100];  // Fill it with numbers using a for-loop for (int i = 0; i < nums.length; i++)     nums[i] = i + 1;  // +1 since we want 1-100 and not 0-99  // Compute sum int sum = 0; for (int n : nums)     sum += n;  // Print the result (5050) System.out.println(sum); 

Answer 2

If all you want to do is calculate the sum of 1,2,3... n then you could use :

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