1. Write a function day_name that receives a number n and returns a pointer to a character
string containing the name of the corresponding day. The day names should be kept in a
static table of character strings local to the function.
2. Write a program to read in an array of names and to sort them in alphabetical order.
Use sort function that receives pointers to the functions strcmp and swap.sort in turn
should call these functions via the pointers.