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change directory (cd) function for an abstract file system ( Java Implementation )

Write a function that provides change directory (cd) function for an abstract file system.

Notes:

Root path is '/'.
Path separator is '/'.
Parent directory is addressable as "..".
Directory names consist only of English alphabet letters (A-Z and a-z).
For example, new Path("/a/b/c/d").cd("../x").getPath() should return "/a/b/c/x".

Note: The evaluation environment uses '\' as the path separator.


public class Path {
    private String path;

    public Path(String path) {
        this.path = path;
    }

    public String getPath() {
        return path;
    }

    public Path cd(String newPath) {
        //throw new UnsupportedOperationException("Waiting to be implemented.");
String[] newP=newPath.split("/");
    String[] oldP=path.split("/");
    int lnCount=0;
    for(String str:newP){
    if(str.equals("..")){
    lnCount++;
    }
    }
   
    int len=oldP.length;
    String strOut="";
    for(int i=0;i<len-lnCount;i++){
    strOut=strOut+oldP[i]+"/";
    }
   
    len=newP.length;
    for(int i=0;i<len;i++){
    if(!newP[i].equals("..")){
    strOut=strOut+newP[i]+"/";
    }
    }
    path=strOut.substring(0, strOut.length()-1);
        System.out.println(path);
    if(path.indexOf("/")<0)
    throw new UnsupportedOperationException("Directory not found");
    return this;
    }

    public static void main(String[] args) {
        Path path = new Path("/a/b/c/d");
        System.out.println(path.cd("../x").getPath());
    }
}


Output:
--------------------

/a/b/c/x


Comments

  1. UnknownNovember 12, 2015 at 3:23 AM

    nice soloution but it should be in other languages also Like PHP

    ReplyDelete
    Replies
    1. UnknownDecember 24, 2015 at 3:36 AM

      For PHP

      class Path
      {
      public $currentPath;

      function __construct($path)
      {
      $this->currentPath = $path;
      }

      public function cd($newPath)
      {
      $newP = explode('/',$newPath);
      $oldP = explode('/', $this->currentPath);

      $inCount = 0;
      foreach($newP as $str) {
      if($str == '..'){
      $inCount++;
      }
      }

      $oldLen = count($oldP);
      $strOut= '';
      for($i=0;$i<($oldLen - $inCount);$i++){
      $strOut .=$oldP[$i]."/";
      }

      $newLen = count($newP);
      for($i=0;$i<$newLen;$i++){
      if($newP[$i] !='..'){
      $strOut = $strOut.$newP[$i].'/';
      }
      }
      $this->currentPath = $strOut;
      }

      }

      Delete
    2. UnknownFebruary 29, 2016 at 12:04 PM

      display '/a/b/c/x'. ????

      Delete
    3. UnknownMarch 31, 2016 at 2:20 AM

      How about C++?

      Delete
    4. UnknownMay 23, 2017 at 6:58 PM

      #include
      #include
      #include

      class Path
      {
      public:

      Path(std::string path)
      {
      currentPath = path;
      }

      std::string getPath() const
      {
      return currentPath;
      }

      Path cd(std::string newPath) const
      {
      Path p = *this;

      if (newPath == "/")
      {
      p.currentPath = "/";

      return p;
      }

      while (newPath.size())
      {
      if (newPath.size() >= 2)
      {
      if (newPath[0] == '.' && newPath[1] == '.')
      {
      if (!p.currentPath.empty())
      {
      p.currentPath.erase(p.currentPath.find_last_of("/\\"));

      if (p.currentPath.empty())
      {
      p.currentPath = "/";
      }
      }

      newPath.erase(0, 2);

      continue;
      }
      }

      if (newPath[0] == '/' || newPath[0] == '\\')
      {
      newPath.erase(0, 1);

      if (newPath[0] == '.')
      continue;
      }

      auto i = newPath.find_first_of("/\\");

      if (p.currentPath.back() != '/' && p.currentPath.back() != '\\')
      {
      p.currentPath += "/";
      }

      p.currentPath += newPath.substr(0, i);

      newPath.erase(0, i);
      }

      return p;
      }

      private:

      std::string currentPath;
      };


      #ifndef RunTests
      int main()
      {
      Path path("/a/b/c/d");
      std::cout << path.cd("../x").getPath();
      }
      #endif

      Delete
  2. UnknownJuly 11, 2017 at 5:41 PM

    how about in python

    ReplyDelete

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