Object-Oriented Programming vs. Functional Programming: Trivial Example in Python

oop_vs_fp.py

#!/usr/bin/env python3

# Object-Oriented Programming:
# - verbose
# - mutable state
class Rounding:

    def __init__(self, granularity):
        self._granularity = granularity

    def roundTo(self, x):
        return round(x * 1 / self._granularity) * self._granularity


# Functional Programming:
# - less code
# - no mutable state
def rounding(granularity):

    def roundTo(x):
        return round(x * 1 / granularity) * granularity

    return roundTo


if __name__ == '__main__':

    rounder = Rounding(0.05)
    print(rounder.roundTo(1.06))
    print(rounder.roundTo(1.02))
    print(rounder.roundTo(0.99))
    print(rounder.roundTo(0.92))

    roundTo = rounding(0.05)
    print(roundTo(1.06))
    print(roundTo(1.02))
    print(roundTo(0.99))
    print(roundTo(0.92))