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 addGrade(self, gradePoint, credits):
        self.hours = credits
        self.qpoints = credits*gradePoint
def main():
    print "This program is a modified version of the student class. It adds"
    print "a mutator method that records a grade and calculates the GPA for"
    print "the student"
    print
 
    stu = Student("stu", 0.0, 0.0)
    while 1:
        print
        grade_str = raw_input("Enter gradepoint or (Enter to quit): ")
        if grade_str == "":
            break
        try:
            grade = float(grade_str)
        except ValueError:
            print "Error, use floating point number"
            return
        print
        credits_str = raw_input("Enter credit hours or (Enter to quit): ")
        if credits_str == "":
            break
        try:
            credits = float(credits_str)
        except ValueError:
            print "Error, use floating point number"
            return
        stu.addGrade(grade, credits)
 
    if stu.getHours() == 0.0 :
        print
        print "Zero gradepoints or credit hours recorded"
        print
    else:
        print "Final GPA = ", stu.gpa()
        print