Python/maths/armstrong_numbers.py
Christian Clauss 46ac50a28e codespell --quiet-level=2 (#1711)
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Python

"""
An Armstrong number is equal to the sum of the cubes of its digits.
For example, 370 is an Armstrong number because 3*3*3 + 7*7*7 + 0*0*0 = 370.
An Armstrong number is often called Narcissistic number.
"""
def armstrong_number(n: int) -> bool:
"""
Return True if n is an Armstrong number or False if it is not.
>>> armstrong_number(153)
True
>>> armstrong_number(200)
False
>>> armstrong_number(1634)
True
>>> armstrong_number(0)
False
>>> armstrong_number(-1)
False
>>> armstrong_number(1.2)
False
"""
if not isinstance(n, int) or n < 1:
return False
# Initialization of sum and number of digits.
sum = 0
number_of_digits = 0
temp = n
# Calculation of digits of the number
while temp > 0:
number_of_digits += 1
temp //= 10
# Dividing number into separate digits and find Armstrong number
temp = n
while temp > 0:
rem = temp % 10
sum += rem ** number_of_digits
temp //= 10
return n == sum
def main():
"""
Request that user input an integer and tell them if it is Armstrong number.
"""
num = int(input("Enter an integer to see if it is an Armstrong number: ").strip())
print(f"{num} is {'' if armstrong_number(num) else 'not '}an Armstrong number.")
if __name__ == "__main__":
import doctest
doctest.testmod()
main()