-----Description-----  
This task involves transforming an array of integers by doubling each element.

-----Input-----  
The input consists of:  
• s: An array of integers.

-----Output-----  
The output is an array of integers where for each valid index i, the element at position i is equal to twice the corresponding element in the input array.

-----Note-----  
The implementation makes use of a recursive helper function to update the array in place. It is assumed that the input array is valid and that the doubling operation does not lead to any overflow issues.