Calc GPA from txt

calcgpa.py

import sys

file = open(sys.argv[1])
gradetotal = 0
pointtotal = 0

def calcGPA(grade,point,method):
	global gradetotal
	global pointtotal
	if method == "HUST":
		g = (grade-75)*0.1+3.0
		if g > 4.0: g = 4.0
		gradetotal += g*point
		pointtotal += point

	if method == "100":
		gradetotal += grade*point
		pointtotal += point

	if method == "4.0":
	    g = grade//10 - 5
	    if grade == 100: g -= 1
	    gradetotal += g*point
	    pointtotal += point

for subject in file:
	[grade, point] = subject.split()
	calcGPA(float(grade),float(point),sys.argv[2])
file.close()

gpa = gradetotal/pointtotal
print(gpa)