How to read an integer from a file and write back it in words to the file in python?

Question

Foe example it reads 123 from file it should write one hundred and twenty three to file

Answer 1

'''
Created on Aug 23, 2019
@author: Anshap
This program converts numbers (in range 0 .. 999) to words
'''
def main():

less20 = ["null", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten",
"eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"]
less100 = ["twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"]

f1 = open('numbers.txt')
f2 = open('words.txt', 'w')
f2.write("Output file converts numbers to words\n")

for line in f1.readlines():
line = line.lstrip();
line = line.rstrip();
if line.isdigit():
if int(line) < 20:
for i in range(20):
if line == str(i):
print(line + " " + less20[i], end='\n')
f2.write(line + " " + less20[i] + '\n')
break
elif int(line) in range(20, 100):
a = int(line) // 10
b = int(line) % 10
if b == 0:
print(line + " " + less100[a-2], end='\n')
f2.write(line + " " + less100[a-2] + '\n')
elif b > 0:
print(line + " " + less100[a-2] + "-" + less20[b], end='\n')
f2.write(line + " " + less100[a-2] + "-" + less20[b] + '\n')

Answer 2

elif int(line) in range(100, 1000):
c = int(line) // 100
d = int(line) % 100
if d == 0:
print(line + " " + less20[c] + " hundred ", end='\n')
f2.write(line + " " + less20[c] + " hundred" + '\n')
elif d > 0:
if d < 20:
for i in range(20):
if str(d) == str(i):
print(line + " " + less20[c] + " hundred and " + less20[i], end='\n')
f2.write(line + " " + less20[c] + " hundred and " + less20[i] + '\n')
break
elif d >= 20:
a = d // 10
b = d % 10
if b == 0:
print(line + " " + less20[c] + " hundred and " + less100[a-2], end='\n')
f2.write(line + " " + less20[c] + " hundred and " + less100[a-2] + '\n')
elif b > 0:
print(line + " " + less20[c] + " hundred and " + less100[a-2] + "-" + less20[b], end='\n')
f2.write(line + " " + less20[c] + " hundred and " + less100[a-2] + '\n')

print("Output file is created.", end='\n')
f1.close()
f2.close()

if __name__ == '__main__':main()