# Check if given integer has only 1s and 0s in it and not another number

Asked 2 days ago
Viewed 14 times

Example:

• `num_1 = 1010`
• `num_2 = 1234`
• `num_3 = 1034`

Here `num_1` is the only valid number since it has both 1s and 0s.

`num_2` is invalid because it does not have any 1s or 0s.

`num_3` should also be invalid since it has digits other than 0s and 1s which are 2 and 4.

Note: you cannot use any `for` loops or `while` loop or any python function or method or string methods or built-in python methods all you can use are `if` `elif` and `else`.

How can we solve this to find the number which has only 1s and 0s in it?

The given integer can be in between the range 0 and 10000.

##### xzavierkihn82
asked 2 days ago

Given the significant set of restrictions:

``````if num == 0: return True
if num == 1: return True
if num == 2: return False
if num == 3: return False
if num == 4: return False
if num == 5: return False
if num == 6: return False
if num == 7: return False
if num == 8: return False
if num == 9: return False
if num == 10: return True
if num == 11: return True
if num == 12: return False
# and so on...
``````
##### meredith78
answered 2 days ago