CIS2107_Lab11_String Library Points: 100 points Objective In this assignment, you'll create your own library of string functions. You'll have the opportunity to practice manipulating strings and managing memory. Additionally, you'll learn the role of header and library files. You may not call functions in string.h but you can use other code in the Standard C Library Task Functions to Include in the Library Implement each of the following functions. Be sure that any string that you create or modify is in fact a string, ie., an array of char terminated with the null character, O Additionally, you should write a driver which tests each of these functions on real data. [2 points] int all_letters (char *s) Returns 1 if all of the characters in the string are either upper- or lower-case letters of the alphabet. It returns 0 otherwise [2 points] num_in_range (char *sl, char b, char t) returns the number of characters c in s 1 such that b