7-1

#! /usr/bin/env python3.2
# -*- coding: utf-8 -*-

# main.py
""" Task: Exercise 7.1
    Write a program to read through a file and print the contents of the file
    (line by line) all in upper case. Executing the program will look as follows:
    python shout.py
    Enter a file name: mbox-short.txt
    FROM STEPHEN.MARQUARD@UCT.AC.ZA SAT JAN 5 09:14:16 2008
    RETURN-PATH: <POSTMASTER@COLLAB.SAKAIPROJECT.ORG>
    RECEIVED: FROM MURDER (MAIL.UMICH.EDU [141.211.14.90])
    BY FRANKENSTEIN.MAIL.UMICH.EDU (CYRUS V2.3.8) WITH LMTPA;
    SAT, 05 JAN 2008 09:14:16 -0500
    You can download the file from www.py4inf.com/code/mbox-short.txt
"""

# Functions
def enterFileName():
    """
    The user has to enter a filename.
    Returns fileName
    """
    fileName = None
    while fileName == None:
        # Enter filename
        try:
            fileName = input("Enter the filename: ")
        except:
            print("Invalid input!")
            continue
    return fileName

# Main
file = None
fileName = enterFileName()
try:
    file = open(fileName, 'r')      # Open file
except:
    print("File cannot be opened: " + str(fileName))
    exit()
if file != None:
    try:
        for line in file:           # Read file content
            print(line.rstrip().upper())    # Print content
    except:
        print("Error on reading file content!")
    try:
        file.close()                # Close file
    except:
        print("File could not be closed!")
        exit()