make some update

Refactor based on Leo’s comment

Author: RogerTongTong

.DS_Store

@@ -0,0 +1 @@
+hahaha

5. File Operations and Exception handling /def.txt

@@ -1,54 +1,65 @@
 #Define a class which contains some common operations to file
 class FileOperator
 
-def newFile (name, path="./")
-  begin
-    puts "Start to create a file..."
-    file = File.new(name, "w")
-  rescue StandardError => e
-    puts e.to_s
-  ensure
-    puts "File is closed"
-    file.close
+  CREATE="create"
+  DELETE="delete"
+  READ="read"
+  APPEND="append"
+
+  def newFile(name, path="./")
+    printStartInfo(CREATE, name)
+    begin
+      file = File.new(name, "w")
+    rescue StandardError => e
+      puts e.to_s
+    ensure
+      closeFile(file)
+    end
   end
-end
 
-def deleteFile(name, path="./")
-  begin
-    puts "Start to delete a file..."
-    File.delete(path+name)
-    puts "File is deleted successfully."
-  rescue StandardError => e
-    puts e.to_s
+  def deleteFile(name, path="./")
+    printStartInfo(DELETE, name)
+    begin
+      File.delete(path+name)
+      puts "File is deleted successfully."
+    rescue StandardError => e
+      puts e.to_s
+    end
   end
-end
 
-def readFile(name, path="./")
-  begin
-    puts "Start to read a file..."
-    file = File.open(path+name, "r")
-    file.readlines
-  rescue StandarError => e
-    puts e.to_s
-  ensure
-    puts "File is closed"
-    file.close
+  def readFile(name, path="./")
+    printStartInfo(READ, name)
+    begin
+      file = File.open(path+name, "r")
+      file.readlines
+    rescue StandarError => e
+      puts e.to_s
+    ensure
+      closeFile(file)
+    end
   end
-end
 
-def appendFile(content, name, path="./")
-  begin
-    puts "Start to append something..."
-    file = File.open(path+name, "w")
-    file.write(content)
-  rescue StandardError => e
-    puts e.to_s
-  ensure
-    puts "File is closed"
-    file.close
+  def appendFile(content, name, path="./")
+    printStartInfo(APPEND, name)
+    begin
+      file = File.open(path+name, "w")
+      file.write(content)
+    rescue StandardError => e
+      puts e.to_s
+    ensure
+      closeFile(file)
+    end
   end
-end
 
+  private
+  def closeFile(file)
+    file.close
+    puts "Files is closed"
+  end
+  
+  def printStartInfo(op, fileName)
+    puts "Start to #{op} a file named #{fileName}"
+  end
 end
 
 op = FileOperator.new