Decimal To Binary (CodeEval) in python 3.x

main.py

# coding=utf-8
import sys


def decimal_to_binary(n):
    if n == 0:
        return '0'
    result = ''
    while n > 0:
        result = str(n % 2) + result
        n //= 2
    return result


def main():
    with open(sys.argv[1], "r") as f:
        for line in f:
            print(decimal_to_binary(int(line.rstrip())))


if __name__ == "__main__":
    main()