#### Sum of Digits

```from timeit import timeit

def sum_of_digits(n: int) -> int:
"""
Find the sum of digits of a number.

>>> sum_of_digits(12345)
15
>>> sum_of_digits(123)
6
>>> sum_of_digits(-123)
6
>>> sum_of_digits(0)
0
"""
n = -n if n < 0 else n
res = 0
while n > 0:
res += n % 10
n = n // 10
return res

def sum_of_digits_recursion(n: int) -> int:
"""
Find the sum of digits of a number using recursion

>>> sum_of_digits_recursion(12345)
15
>>> sum_of_digits_recursion(123)
6
>>> sum_of_digits_recursion(-123)
6
>>> sum_of_digits_recursion(0)
0
"""
n = -n if n < 0 else n
return n if n < 10 else n % 10 + sum_of_digits(n // 10)

def sum_of_digits_compact(n: int) -> int:
"""
Find the sum of digits of a number

>>> sum_of_digits_compact(12345)
15
>>> sum_of_digits_compact(123)
6
>>> sum_of_digits_compact(-123)
6
>>> sum_of_digits_compact(0)
0
"""
return sum(int(c) for c in str(abs(n)))

def benchmark() -> None:
"""
Benchmark code for comparing 3 functions,
with 3 different length int values.
"""
print("\nFor small_num = ", small_num, ":")
print(
"> sum_of_digits()",
"\t\tans =",
sum_of_digits(small_num),
"\ttime =",
timeit("z.sum_of_digits(z.small_num)", setup="import __main__ as z"),
"seconds",
)
print(
"> sum_of_digits_recursion()",
"\tans =",
sum_of_digits_recursion(small_num),
"\ttime =",
timeit("z.sum_of_digits_recursion(z.small_num)", setup="import __main__ as z"),
"seconds",
)
print(
"> sum_of_digits_compact()",
"\tans =",
sum_of_digits_compact(small_num),
"\ttime =",
timeit("z.sum_of_digits_compact(z.small_num)", setup="import __main__ as z"),
"seconds",
)

print("\nFor medium_num = ", medium_num, ":")
print(
"> sum_of_digits()",
"\t\tans =",
sum_of_digits(medium_num),
"\ttime =",
timeit("z.sum_of_digits(z.medium_num)", setup="import __main__ as z"),
"seconds",
)
print(
"> sum_of_digits_recursion()",
"\tans =",
sum_of_digits_recursion(medium_num),
"\ttime =",
timeit("z.sum_of_digits_recursion(z.medium_num)", setup="import __main__ as z"),
"seconds",
)
print(
"> sum_of_digits_compact()",
"\tans =",
sum_of_digits_compact(medium_num),
"\ttime =",
timeit("z.sum_of_digits_compact(z.medium_num)", setup="import __main__ as z"),
"seconds",
)

print("\nFor large_num = ", large_num, ":")
print(
"> sum_of_digits()",
"\t\tans =",
sum_of_digits(large_num),
"\ttime =",
timeit("z.sum_of_digits(z.large_num)", setup="import __main__ as z"),
"seconds",
)
print(
"> sum_of_digits_recursion()",
"\tans =",
sum_of_digits_recursion(large_num),
"\ttime =",
timeit("z.sum_of_digits_recursion(z.large_num)", setup="import __main__ as z"),
"seconds",
)
print(
"> sum_of_digits_compact()",
"\tans =",
sum_of_digits_compact(large_num),
"\ttime =",
timeit("z.sum_of_digits_compact(z.large_num)", setup="import __main__ as z"),
"seconds",
)

if __name__ == "__main__":
small_num = 262144
medium_num = 1125899906842624
large_num = 1267650600228229401496703205376
benchmark()
import doctest

doctest.testmod()
```  