def main():
    print "This program sorts student grade information"
    filename = raw_input("Enter the name of the data file: ")
    dfield = raw_input("Enter gpa, name, or credits to sort: ")
    filename = raw_input("Enter a name for the output file: ")
    data = readStudents(filename)
    ...

    if dfield == gpa:
        data.sort(cmpgpa)

    if dfield == 'gpa':
        data.sort(cmpgpa)

def makeStudent(infoStr):
    print string.split(infoStr,"\t")  # test --> ['Computewell, Susan 100 400\n']
    name, hours, qpoints = string.split(infoStr,"\t")
    return Student(name, hours, qpoints)

# save as p2sort.py
from p2gpa import Student, makeStudent
def readStudents(filename):
    infile = open(filename, 'r')
    students = []
    for line in infile:
        students.append(makeStudent(line))
    infile.close()
    return students
 
def writeStudents(students, filename):
    outfile = open(filename, 'w')
    for s in students:
        print "%-20s %0.2f %0.2f" % (s.getName(), s.gpa(), s.getHours())  # test
        outfile.write("%s\t%0.2f\t%0.2f\n" %
                      (s.getName(), s.getHours(), s.getQPoints()))
    outfile.close()
 
# for these compares s1 and s2 are class instances ...
def cmpgpa(s1, s2):
    # low to high
    #return cmp(s1.gpa(), s2.gpa())
    # high to low
    return cmp(s2.gpa(), s1.gpa())
def cmpname(s1, s2):
    #return cmp(s1.name(), s2.name())  # problems!!!?
    return cmp(s1.getName(), s2.getName())
def cmpcredits(s1, s2):
    # low to high
    #return cmp(s1.getHours(), s2.getHours())
    # high to low
    return cmp(s2.getHours(), s1.getHours())
 
def main():
    print "This program sorts student grade information"
    # file has line format -->  name tab hours tab qpoints
    file_in = raw_input("Enter the name of the data file: ")
    dfield = raw_input("Enter gpa, name, or credits to sort: ")
    # data is a list of Student class instances
    data = readStudents(file_in)
    if dfield == 'gpa':
        data.sort(cmpgpa)
    elif dfield == 'name':
        data.sort(cmpname)
    else:
        data.sort(cmpcredits)
    file_out = raw_input("Enter a name for the output file: ")
    writeStudents(data, file_out)
    print "The data has been written to", file_out
 
if __name__ == '__main__':
    main()

# save this module file as p2gpa.py
import string
#import math
class Student:
    def __init__(self, name, hours, qpoints):
        self.name = name
        self.hours = float(hours)
        self.qpoints = float(qpoints)
    def getName(self):
        return self.name
    def getHours(self):
        return self.hours
    def getQPoints(self):
        return self.qpoints
    def gpa(self):
        return self.qpoints/self.hours
    def name(self):
        return self.name
 
def makeStudent(infoStr):
    if '\t' in infoStr:
        #print string.split(infoStr,"\t")  # test --> ['Computewell, Susan ', '100 ', '400\n']
        name, hours, qpoints = string.split(infoStr,"\t")
    return Student(name, hours, qpoints)
def main():
    filename = raw_input("Enter name the grade file: ")
    infile = open(filename, 'r')
    best = makeStudent(infile.readline())
    for line in infile:
        s = makeStudent(line)
        if s.gpa() > best.gpa():
            best = s
    infile.close()
    print "The best student is:", best.getName()
    print "hours:", best.getHours()
    print "GPA:", best.gpa()
 
# test the module ...
if __name__ == '__main__':
    main()
    #raw_input("Press Enter to go on ... ")

# this will create a sample data file with tab separators
data = [['Computewell, Susan', 100, 400],
['DibbleBit, Denny', 18, 41.5],
['Jones, Jim', 48.5, 155],
['Smith, Frank', 37, 125.33],
['Adams, Henry', 127, 228]]
fout = open("in.txt", "w")
for line in data:
    text = "%s\t%s\t%s\n" % (line[0], line[1], line[2])
    print text,
    fout.write(text)
fout.close()