#
# Author:  James Tam

# Version: October 29, 2013 (Initialization occurs in a separate function)
# Version: October 26, 2011 (Port to Python V3.X)
#
# The second version of a program that tracks the grades for a class.
# 

# Global constant to specify the size of the list.
CLASS_SIZE = 5

# Creates a list with 5 elements.
# Each element is set to (an invalid) default grade
def initialize():
    classGrades = []
    # Create a list with 5 elements with each element initialized to zero
    # Within the body of the loop create a new list element that contains 0
    # and append / add it to the end of the list.
    for i in range (0, CLASS_SIZE, 1):
        classGrades.append(-1)
    return(classGrades)

# Step through the list an element at a time and get the user to input the
# grades.
def read(classGrades):
    total = 0
    average = 0
    for i in range (0, CLASS_SIZE, 1):
        # Because list indices start at zero add one to the student number.
        temp = i + 1
        print("Enter grade for student no.", temp, ":")
        classGrades[i] = float(input (">"))
        total = total + classGrades[i]
    average = total / CLASS_SIZE
    return(classGrades, average)

# Traverse the list and display the grades.
def display(classGrades, average):
    print()
    print("GRADES")
    print("The average grade is %.2f%%" %average)
    for i in range (0, CLASS_SIZE, 1):
        # Because list indices start at zero add one to the student number.
        temp = i + 1
        print("Student No. %d: %.2f%%" %(temp,classGrades[i]))


# PROGRAM BEGINS EXECUTION HERE
def start():
    classGrades = initialize()
    classGrades, average = read(classGrades)
    display(classGrades,average)

start()