Write a C program 'myls' that functions like the unix command 'ls'.
Specifically, 'myls' is a program that displays the file list under the current directory. The file list are displayed in different format as commanded by different flags of:
-F: File names are displayed in 5 columns. Each of them are marked according to the type of file of it. Only the following 3 types are required:
'*': for regular executables.
'/': for directories.
'@': for symbolic link.
-l: File names are displayed a row each. Full I-node info are displayed in the way similar to "ls -l" does. However, the path as displayed by "ls -l" can be omitted.
no flag: File names are displayed in the plain format. They are printed in 5 columns of 16-char wide each.