globalvariable_example.py

#A Function that gets the course data and returns the course raw grade
#if this function is called a second time because the user inputed a wrong grade value
#it skips asking for the users name and course unit
#this is because the counter variable which we use to track how many times the
#course data function is being called will no longer be Zero
counter  = 0

def course_data():
    # the word global infront of counter tells python we are refering to the counter
    # variable defined outside this function
    # we shall study more about global variables when we study about function scopes
    global counter
    if counter == 0:
        #ask for user name course etc if counter is 0
        name=raw_input("Name: ")
        course=raw_input("Course: ")
        course_unit=raw_input("course_unit1: ")
        counter=counter+1
    else:
        print("You already gave us your details Just get us Your grade: ")
    grade=raw_input("Course Grade: ")
    return grade

#function that gets the computed grade (logic)
def computed_grade(user_grade):
    # definining grade value variable as an intially empty variable
    grade_value = None
     #The index of the element corresponds to its value
    grade_list = ["F","O","E","D","C","B","A"]
    index = 0
    for g in grade_list:
        print("g is : "+g+ " index is : "+ str(index))
        print("User grade: "+user_grade)
        #index=grade_list.index(g)
        if user_grade == g :
            grade_value = index
        index=index+1
    #alternatively we can use "index=grade_list.index(g)" as opposed to defining index = 0 and then iterating over it with "index=index+1"
    # user entered invalid grade that we dont have in our list. The step has been commented in the code above.
    if grade_value == None:
        print("entered wrong grade, Please re-enter your grades one more Time: ")
        main()
    else:
          print ("Your grade value is : "+str(grade_value))
          return grade_value

# def determining_performance(grade):
#     if grade >= 4:
#         print("good performance")
#     elif  grade >=2 and grade < 4:
#         print("average score")
#     else:
#         print("poor performance")

#putting all our function in one function so that we make only one function call to run our progra
def main():
    raw_grade = course_data()
    grade_value=computed_grade(raw_grade)
    # determining_performance(grade_value)
#run our program
main()