5. (15 pts) Consider the following recursive sum_first_N function. This function takes an array (arr) and an integer (N) and it calculates the sum of first N values in the array 'arr'. A sample main function that calls sum_first_N is also provided. (a) (15 pts) sum_first_N is not tail-recursive. Rewrite the sum_first_N using tail-recursion. Name your function sum_first_N_tail. (b) (5pts) Rewrite sum_first_N without using recursion (i.e., using a while loop). in C++