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File Systems

File Systems. Files and directories Absolute and relative names Text and binary files Sequential-access and random-access files. File System Input and Output. One time access vs over-a-period-of- time access One time: call a static member function

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File Systems

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  1. File Systems • Files and directories • Absolute and relative names • Text and binary files • Sequential-access and random-access files

  2. File System Input and Output One time access vs over-a-period-of- time access One time: call a static member function Over-a-period-of- time: create an instance of a class Classes for Directories Directory DirectoryInfo Classes for Files File FileInfo

  3. File and FileInfo in C++/CLI • File::Exists(path) • FileInfo^ file = gcnew FileInfo( path ); • file->Exists • file->FullName • file->Length • file->Directory • file->isReadOnly • file->CopyTo( path2 ) • http://msdn.microsoft.com/en-us/library/system.io.file.aspx • http://msdn.microsoft.com/en-us/library/system.io.fileinfo.aspx

  4. Directory and DirectoryInfo in C++/CLI • Directory::Exists(path) • DirectoryInfo^ dir=gcnew DirectoryInfo(path); • dir->Exists • dir->FullName • dir->Parent • array<FileInfo^>^ GetFiles() • array<DirectoryInfo^>^ GetDirectories() • http://msdn.microsoft.com/en-us/library/system.io.directory.aspx • http://msdn.microsoft.com/en-us/library/system.io.directoryinfo.aspx

  5. Opening Files and I/O • Open, Create, OpenRead, etc. • Open Methods • Mode: Append, Create, CreateNew, Open, etc • Access: Read, Write, ReadWrite • Share: None, Read, Write, ReadWrite • Stream, FileStream, StreamWriter, StreamReader

  6. Sequential-access Text File in C++/CLI • StreamReader ^sr = File::OpenText(name); // or: • StreamReader ^sr = gcnew StreamReader(name); • sr->Read(); // read one char • sr->ReadLine(); // read one line • sr->Close() • StreamWriter ^sw = gcnew StreamWriter(name); • sw->Write(“string”); • sw->WriteLine(“string”); • sw->Close()

  7. Object Serialization in C++/CLI • Dealing with complex classes • [Serializable] ref class MyObject {} • BinaryFormatter: • using namespace System::Runtime::Serialization::Formatters::Binary; • SoapFormatter: • // Simple Objet Access Protocol, XML • #using <System.Runtime.Serialization.Formatters.Soap.dll> • using namespace System::Runtime::Serialization::Formatters::Soap;

  8. Object Serialization in C++/CLI cont’d Serialization steps: • BinaryFormatter ^bf = gcnew BinaryFormatter() // SoapFormatter, XML-based • FileStream output = File::Create(name); • bf->Serialize(output, obj); // Store MyObject obj; • output.close(); • BinaryFormatter ^bf = gcnew BinaryFormatter() • FileStream input = File::OpenRead(name); • MyObject^ obj = (MyObject^)bf->Deserialize(input); //Restore MyObject obj • input.close();

  9. An Example • … • Also, • Command line parameters: • “Project” -> “Properties” -> “Configuration Properties” -> “Debugging” • On that page, find “Command Arguments”, add the file name

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