Python/maths/armstrong_numbers.py
Akash f80ffe1f54
added method for checking armstrong number (#1936)
* added method for checking armstrong number

* Update comment

Co-authored-by: Christian Clauss <cclauss@me.com>
2020-05-03 19:56:33 +02:00

67 lines
1.9 KiB
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 narcissistic_number(n:int) -> bool:
"""Return True if n is a narcissistic number or False if it is not"""
expo = len(str(n)) #power, all number will be raised to
temp = [(int(i)**expo) for i in str(n)] # each digit will be multiplied expo times
# check if sum of cube of each digit is equal to number
return n == sum(temp)
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.")
print(f"{num} is {'' if narcissistic_number(num) else 'not '}an Armstrong number.")
if __name__ == "__main__":
import doctest
doctest.testmod()
main()