Question: Write Simple Directory Traversal Program. Write a program using either Java, C#, or C++ that simulates the directory listing commands of popular operating command shells.
Write Simple Directory Traversal Program.
Write a program using either Java, C#, or C++ that simulates the directory listing commands of popular operating command shells. You will support the following commands:
list
lists the entries in the current directory horizontally
listall
prints a hierarchical listing of the current directory subtree (starting from the current node)
chdir
changes directory to the named, adjacent subdirectory
up
moves up the tree to the parent (like cd ..)
count
prints the number of files (not directories) in the current directory
countall
prints the number of files (not directories) in the subtree starting from the current node
q
quit the program
You will begin by reading in a file that contains a directory tree. Here is a sample:
top:
file1
middle:
file2
file3
bottom:
file4
file5
file6
file7
another:
file8
Directories end with a colon. Print a prompt with the current directory name. Here is a sample session using the sample tree:
top> listall
top:
file1
middle:
file2
file3
bottom:
file4
file5
file6
file7
another:
file8
top> count
2
top> countall
8
top> chdir file1
no such directory
top> chdir middle
middle> list
file2 file3 bottom file6
middle> listall
middle:
file2
file3
bottom:
file4
file5
file6
middle> count
3
middle> up
top> list
file1 middle file7 another
top> chdir another
another> list
file8
another> up
top> chdir middle
middle> chdir bottom
bottom> list
file4 file5
bottom> ip
invalid command
bottom> up
middle> up
top> q
Needless to say, youll be reading into a composite structure.
Heres a sample main program (but you dont have to have an Explorer class):
int main() {
ifstream in("directory.dat");
Explorer exp(DirectoryFactory::createDirTree(in));
exp.process(cin, cout);
}
Explorer is a wrapper for the composite and interprets user commands and calls the right component methods, while keeping track of the current directory. Enjoy! (C++ programmers: beware memory leaks!)
Design Note:
This is obviously an exercise in using the Composite pattern and internal iteration. A good way to lose at least 15 points is to write or use a method that identifies the subtype of an object, such as isLeaf().
Do NOT use external iteration. (Dont write an Iterator.) Unless you want to make it much harder than it has to be
In the input file, subdirectories are indicated by series of three spaces.
Listall: when you are in a subdirectory, and you do a listall, start the current level at the left side.
Here are the two .dat files
directory.dat
top: file1 middle: file2 file3 bottom: file4 file5 file6 file7 another: file8
MyProg6TESTdirectory.dat
top: file1 middle: file2 file3 bottom: file4 reallydeep: deepfile1 deepfile2 deepfile3 deepfile4 file5 file6 file7 another: file8 adeeper1: adeeper2: adeepest: waywaydeep: file9 yetanother:
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