Percentage Range to GPA - Python

ReadMe.md

Percentage Range to GPA - Python

How to use this program:

1. Run with Python: python[3] main.py
2. Input a grade percentage (0 to 100, inclusive, no symbols, decimals accepted)
3. The program will return the GPA for that percentage

main.py

def percent_to_gpa(percent):
    """Convert a percentage (0 to 100) to a GPA"""
    if percent >= 95:
        return 4.0
    elif percent < 65:
        return 0.0
    else:
        # rounds down to 1 decimal place
        return int((4 - (95-percent)/10.0) * 10) / 10.0


def is_valid_range(percent):
    """Check that a given percentage is within valid range (0 to 100 inclusive)"""
    return percent >= 0 and percent <= 100

def prompt():
    """Prompt for a grade percentage"""
    return input("--- Input a grade percentage ([0 to 100], q to quit): ")


def test():
    """Test the program with boundary inputs"""
    assert percent_to_gpa(95) == 4.0
    assert percent_to_gpa(65) == 1.0
    assert percent_to_gpa(64.9) == 0.0
    assert percent_to_gpa(87) == 3.2
    assert percent_to_gpa(73.1) == 1.8
    assert percent_to_gpa(72.9) == 1.7


def main():
    """Prompts the user for percentages until they decide to quit"""
    text = prompt()
    while text != 'q':
        try:
            percent = float(text)
            if is_valid_range(percent):
                print('GPA:', percent_to_gpa(percent))
            else:
                print('***', percent, 'is out of range [0 to 100]')
        except Exception as e:
            print('*** Unable to parse', text, ': ', e)
        text = prompt()
    print('*** Exiting')

test()
main()