# Exercise 7.1
filename = raw_input('Enter a filename: ')
try:
    with open(filename, 'r') as fhandle:
        for line in fhandle:
            print line.rstrip().upper()
except IOError as err:
    print "File error: " + str(err)

# Exercise 7.2
filename = raw_input('Enter a filename: ')
spamconf = []
try:
    with open(filename, 'r') as fhandle:
        for line in fhandle:
            if line.startswith('X-DSPAM-Confidence'):
                spamconf.append(float(line.split()[1]))
        print "Average spam confidence: %s" % str((sum(spamconf)) / len(spamconf))
except IOError as err:
    print "File error: " + str(err)

# Exercise 7.3
import sys
filename = raw_input('Enter a filename: ')
if filename == 'na na boo boo':
    print filename.upper() + " TO YOU - You have been punk'd"
    sys.exit()
spamconf = []
try:
    with open(filename, 'r') as fhandle:
        for line in fhandle:
            if line.startswith('X-DSPAM-Confidence'):
                spamconf.append(float(line.split()[1]))
        print "Average spam confidence: %s" % str((sum(spamconf)) / len(spamconf))
except IOError as err:
    print "File error: " + str(err)