Write a C program myls2 whose behavior resembles that of the system command ls. myls2 must print the names of files in the current directory in columns of equal width. myls2 must accept the following parameters:

$ myls2 [-rs] 

-s switch sorts the filenames in the lexicographical order. The file names must be arranged in sequence so that the names in column 1 are followed by the names in column 2, and so on.

-r switch sorts the filenames in the reverse lexicographical order.

When no switches are present, myls2 does not need to sort the file names.

Consider using the qsort() library function that implements the quicksort algorithm to sort an array.

$ ls dirA

file0.txt file4.txt file7.txt

file1.txt file5.txt file8.txt

file2.txt file6.txt file9.txt

file3.txt

$ cd dirA

$ ls

file0a.txt file444444444a.txt file7a.txt

file1a.txt file5a.txt file8a.txt

file2a.txt file6a.txt file9a.txt

file3a.txt