# JavaScript: Compute the sum of two parts and store into an array of size two

## JavaScript Basic: Exercise-85 with Solution

Write a JavaScript program to divide a given array of positive integers into two parts. First element belongs to the first part, second element belongs to the second part, and third element belongs to the first part and so on. Now compute the sum of two parts and store it in an array of size two.

**Visual Presentation:**

**Sample Solution: **

**JavaScript Code:**

```
// Function to calculate alternate sums of elements in an array
function alternate_Sums(arr) {
var result = [0, 0]; // Initialize an array to store alternate sums
for(var i = 0; i < arr.length; i++)
{
if(i % 2) result[1] += arr[i]; // If index is odd, add the element to the second sum
else
result[0] += arr[i]; // If index is even, add the element to the first sum
}
return result; // Return the array of alternate sums
}
// Example usage
console.log(alternate_Sums([1, 3, 6, 2, 5, 10])); // Output: [14, 8]
```

Output:

[12,15]

**Live Demo: **

See the Pen javascript-basic-exercise-85 by w3resource (@w3resource) on CodePen.

**Flowchart: **

**ES6 Version:**

```
// ES6 version with comments
// Function to calculate alternate sums of elements in an array
const alternate_Sums = (arr) => {
var result = [0, 0]; // Initialize an array to store the alternate sums [sum1, sum2]
for(var i = 0; i < arr.length; i++)
{
if(i % 2) result[1] += arr[i]; // If the index is odd, add the element to the second sum
else
result[0] += arr[i]; // If the index is even, add the element to the first sum
}
return result; // Return the array with alternate sums
};
// Example usage
console.log(alternate_Sums([1, 3, 6, 2, 5, 10]));
```

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