Adding Armstrong number

maths/armstrong_numbers.py

@@ -0,0 +1,50 @@
+""" An Armstrong number is a number that 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):
+    """
+        This function checks if a number is Armstrong or not.
+
+        >>> armstrong_number(153)
+        True
+        >>> armstrong_number(200)
+        False
+        >>> armstrong_number(1634)
+        True
+        """
+    # 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 = sum + (rem ** number_of_digits)
+        temp //= 10
+    return n == sum
+
+
+# In main function user inputs a number to find out if it's an Armstrong or not. Th function armstrong_number is called.
+def main():
+    num = int(input("Enter a number to check if it is Armstrong or not: ").strip())
+    armstrong_number(num)
+    if armstrong_number(num):
+        print(num, " is an Armstrong number")
+    else:
+        print(num, " is not an Armstrong number")
+
+
+if __name__ == '__main__':
+    main()
+    import doctest
+
+    doctest.testmod()
+