Create number_of_digits.py (TheAlgorithms#1975)

* Create number_of_digits.py

A python program to find the number of digits in a number.

* Update number_of_digits.py

* Update number_of_digits.py

* Add TheAlgorithms#1976 to get Travis CI to pass

TheAlgorithms#1976

* Add type hints as discussed in CONTRIBUTING.md

Co-authored-by: Christian Clauss <[email protected]>

Author: 2 people

maths/number_of_digits.py

@@ -0,0 +1,18 @@
+def num_digits(n: int) -> int:
+    """
+    Find the number of digits in a number.
+
+    >>> num_digits(12345)
+    5
+    >>> num_digits(123)
+    3
+    """
+    digits = 0
+    while n > 0:
+        n = n // 10
+        digits += 1
+    return digits
+
+
+if __name__ == "__main__":
+    print(num_digits(12345))   # ===> 5