Convert an integer to binary without using the built-in bin function

Question

This function receives as a parameter an integer and should return a list representing the same value expressed in binary as a list of bits, where the first element in the l

Answer 1

# dec2bin.py
# FB - 201012057
import math

def dec2bin(f):
    if f >= 1:
        g = int(math.log(f, 2))
    else:
        g = -1
    h = g + 1
    ig = math.pow(2, g)
    st = ""    
    while f > 0 or ig >= 1: 
        if f < 1:
            if len(st[h:]) >= 10: # 10 fractional digits max
                   break
        if f >= ig:
            st += "1"
            f -= ig
        else:
            st += "0"
        ig /= 2
    st = st[:h] + "." + st[h:]
    return st

# MAIN
while True:
    f = float(raw_input("Enter decimal number >0: "))
    if f <= 0: break
    print "Binary #: ", dec2bin(f)
    print "bin(int(f)): ", bin(int(f)) # for comparison