"""
Grade Sheet Example for Dictionaries

Author: Walker M. White (wmw2)
Date:   September 20, 2017 (Python 3 Version)
"""

# Global variable store the grade sheet
GRADES = {'js1':80,'js2':92,'wmw2':50,'aa1':95}

def max_grade(grades):
    """
    Returns: maximum grade in the grade dictionary
    
    Precondition: grades has netids as keys, ints as values
    """
    maximum = 0
    for v in grades.values():
        if v > maximum:
            maximum = v
    
    return maximum


def netids_above_cutoff1(grades,cutoff):
    """
    Returns: list of netids with grades above or equal cutoff
    
    Precondition: grades has netids as keys, ints as values.
    cutoff is an int.
    """
    result = [] # start with an empty list
    for k in grades:
        if grades[k] >= cutoff:
            result.append(k)  # Add k to the list result
    
    return result


def netids_above_cutoff2(grades,cutoff):
    """
    Returns: list of netids with grades above or equal cutoff
    
    Precondition: grades has netids as keys, ints as values.
    cutoff is an int.
    """
    result = [] # start with an empty list
    for k,v in grades.items():
        if v >= cutoff:
            # NOTE: Alternate way to append to list
            result = result+[k]  # Put k in a list and concatenate to end
    
    return result


def give_extra_credit(grades,netids,bonus):
    """
    Gives bonus points to everyone in sequence netids
    
    This is a PROCEDURE.  It modifies the contents of grades.
    It only modifies elements of grades with a key that appears
    in the sequence netids.
    
    Precondition: grades has netids as keys, ints as values.
    netids is a sequence of strings whose elements are all
    keys in grades (though not all keys appear in netids).
    Bonus is an int.
    """
    for student in netids:
        if student in grades: # tests if student is a key in grades
            grades[student] = grades[student]+bonus