File Viewer


DESIGN DOCUMENT


COMPONENT: class FileViewer

A simple file viewer.  See program specification for details.

Public method:

o void run()

    Runs the viewer.  
    
Implementation note: Holds the lines of text in a Buffer object.  The displaying of the buffer contents and the execution of the commands is delegated to the Buffer object.

Collaborator: Buffer.


COMPONENT: class Buffer

A buffer for a simple file viewer.  Holds the lines of text and executes commands on them.  Displays the contents of the buffer.  See program specification for details on commands.

Public methods:
          
o Buffer() 

    Creates an empty buffer. 

o void display() const

    Displays the lines of text that the user is currently viewing. 
    
o const string & file_name() const

    Returns the name of the file. Returns an empty string if no file is open.

o void move_to_next_page() 
  void move_to_previous_page() 
  bool open(const string & file_name)
  
    Executes the corresponding file viewer command on the buffer.  See program specification for details.  The method open returns true if successful.
    
o void set_window_height(int h)

    Self-explanatory.

Implementation note:  Stores each line of text as a string and all the lines in a vector.  Also stores the name of the file and the window height.