language is in C.

Exercise 3.21. String manipulation functions are often vulnerable to ill- formed C strings: character arrays that lack string terminators. For example, if copyString of Exercise 3.19 is given an ill-formed string as in, it will read and write through memory until a 0 is found or until a segmentation fault occurs. Write a protected version of copyString that transfers at most n - 1 characters from in to out and always writes a string terminator to out. * 1/* Copies at most n-1 characters of string in into the 2 * buffer pointed to by out. If n is reached, returns -2. 3 * Otherwise, returns -1 for malformed input and O upon 4 * successful completion. * * 6 int copyStringN (char * in, char * out, int n); Implement a unit test of copyStringN in a main function that exercises its full protective functionality