# ref.

# https://docs.python.org/3.9/library/decimal.html

import decimal

# python3

# Solve the accuracy problem

def exmaple_1():

print(decimal.Decimal(3.499))

print(decimal.Decimal('3.499')) # It is recommended to use str.

def exmaple_2():

float_a = 1.0

float_b = 0.8

print('float_a-float_b = ', float_a - float_b)

def exmaple_2_fix():

decimal_a = decimal.Decimal('1.0')

decimal_b = decimal.Decimal('0.8')

print('float_decimal-float_decimal = ', decimal_a - decimal_b)

def exmaple_3():

print(round(1.5))

print(round(2.5))

def exmaple_3_fix():

# ROUND_HALF_UP is the same as Python 2.X's old behavior.

print(decimal.Decimal('1.5').quantize(decimal.Decimal('1.'),rounding=decimal.ROUND_HALF_UP))

print(decimal.Decimal('2.5').quantize(decimal.Decimal('1.'),rounding=decimal.ROUND_HALF_UP))

def exmaple_4():

print(decimal.Decimal('3.4999').quantize(decimal.Decimal('1.'),rounding=decimal.ROUND_HALF_UP))

def exmaple_5():

print(decimal.Decimal('3.4999').quantize(decimal.Decimal('1.'),rounding=decimal.ROUND_DOWN))

def exmaple_6():

a = 1.0-0.8

print(decimal.Decimal(a))

print(decimal.Decimal(a).quantize(decimal.Decimal('1.'),rounding=decimal.ROUND_DOWN))

if __name__ == "__main__":

exmaple_1()

# exmaple_2()

# exmaple_2_fix()

# exmaple_3()

# exmaple_3_fix()

# exmaple_4()

# exmaple_5()

# exmaple_6()