Several fixes to file r/w example.

1) appends / to the end of the file path if the user forgot.
2) displays warning and asks for overwrite confirmation of the output file already exists.
3) exceptions caught while reading/writing files.
4) a small grammar correction.

1 files changed, 42 insertions, 22 deletions

diff --git a/data/GSOC examples/file writing and reading b/data/GSOC examples/file writing and reading
index 13b7436..bc01e01 100644
--- a/data/GSOC examples/file writing and reading
+++ b/data/GSOC examples/file writing and reading
@@ -1,41 +1,61 @@
 import time
+import os
+import sys
 
 print "This example demonstrates how to create a text file, write something to it and then read what we wrote."
 
-print "How shall we call the file?"
+print "What shall we call the file?"
 filename = raw_input()
 
 print "Where would you like to store the file? (can be left empty)"
 # Practice: Where does the file get stored if we leave this empty?
 directory = raw_input()
+if len(directory) != 0 and directory[-1] != "/":
+    directory = directory + "/"
 
 full_name = directory + filename
-
+if os.path.exists(full_name):
+    print "Warning: That file already exists, will be overwritten if you continue!"
+    print "Continue? (yes/no)"
+    cont = raw_input()
+    if cont == "no":
+        print "Aborting..."
+        sys.exit()
+    elif cont != "yes" and cont != "no":
+        print "Wrong input, aborting..."
+        sys.exit()
+    
 print "Please enter the text you would like to store."
 text = raw_input()
 
-# Open the file in the "w"rite mode.
-my_file = open(full_name, "w")
-
-# Let's write the current time to that file.
+# Let's also write the current time to that file.
 # \n is the way of saying "i'm finished with that line, move to the next one."
 current_time = time.ctime()
-my_file.write("The following text was written at: " + current_time + "\n")
-
-# Write our text to the open file.
-my_file.write(text)
-my_file.write("\n")
-
-# Close the file.
-my_file.close()
-
-# Now lets read from that same file. This is how reading is done.
-# First: Open the file in "r"ead mode.
-my_file = open(full_name, "r")
-# Second: Read from it.
-from_file = my_file.read()
-# Third: Close the file.
-my_file.close()
+
+try:
+    # Open the file in the "w"rite mode.
+    my_file = open(full_name, "w")
+    # Write the current time:
+    my_file.write("The following text was written at: " + current_time + "\n")
+    # Write our text:
+    my_file.write(text)
+    my_file.write("\n")
+    # Close the file.
+    my_file.close()
+except:
+    print "An error occured in the writing phase!"
+
+try:
+    # Now lets read from that same file. This is how reading is done.
+    # First: Open the file in "r"ead mode.
+    my_file = open(full_name, "r")
+    # Second: Read from it.
+    from_file = my_file.read()
+    # Third: Close the file.
+    my_file.close()
+except:
+    print "An error occured in the reading phase!"
+
 
 # Print what we've read.
 print from_file