Write a recursive binarySearch function for an array of strings $($already sorted$),$ that

returns the indexes of all the strings whose first letter is b for example.

For example, for anArray $=\{$books$,$ letter, boxes, curve$\},$ the search result should

show: indexes found are: $\{0,2\}.$

Notes: You should set the target letter to be a variable, so we can use your function to

search strings starting with any given letter withing a$-$z$.$

$2.$ Write a main$()$ function that tests the above function, with two test cases.

do it in c$++$