File Reading problems in Python - string

Question

While Reading the files in python using
f = open ("filename.txt")
and accessing the data with
f.read(1)
and finally finding the position of stream usibg
f.tell()
for every step; We get a continous numbering starting from 0 to the current position.
The problem i am facing is that i am actually getting a random number as f.tell() for some positions and then continung the numbers.
For examle, the f.tell() outputs look something ike the following
0
1
2
3
133454568679978
6
7
8...
Any idea why this is happening?
My Code :
f=open("temp_mcompress.cpp")
current = ' '
while current != '' :
print(f.tell())
current = f.read(1)
f.close()
Temp_mcompress.cpp file :
#include <iostream>
int main(int a)
{
}
OUtput :
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
18446744073709551636
18446744073709551638
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
18446744073709551655
40
41
43
44

Answer 1

It seems I might have found the problem which may still be applicable to python 3.x:
source: http://docs.python.org/2.4/lib/bltin-file-objects.html
tell()
Return the file's current position, like stdio's ftell().
Note: On Windows, tell() can return illegal values (after an fgets())
when reading files with Unix-style line-endings. Use binary mode
('rb') to circumvent this problem.