TheAlgorithms-Ruby/maths/armstrong_number.rb
2021-05-07 20:14:06 +05:30

57 lines
1.4 KiB
Ruby

# A ruby program to find a given number is armstrong number or not
# Wiki url: https://en.wikipedia.org/wiki/Narcissistic_number
# other resources: https://pages.mtu.edu/~shene/COURSES/cs201/NOTES/chap04/arms.html
#
# Examples: -> 153 = (1 * 1 * 1) + (5 * 5 * 5) + (3 * 3 * 3) [Armstrong number] and -> 125 != (1 * 1 * 1) + (2 * 2 * 2) + (5 * 5 * 5)
# -> 1634 = (1 * 1 * 1 * 1) + (6 * 6 * 6 * 6) + (3 * 3 * 3 * 3) + (4 * 4 * 4 * 4)
#
def armstrong_number(number)
num = number
sum = 0
len = number.digits.count
while(number != 0)
remainder = number % 10
sum += remainder ** len
number /= 10
end
if num == sum
"The number #{num} is an Armstrong number."
else
"The number #{num} is not an Armstrong number."
end
rescue
"Error: Please provide number only!"
end
#
# Valid inputs
#
puts armstrong_number(153)
# The number 153 is an Armstrong number.
puts armstrong_number(0)
# The number 0 is an Armstrong number.
puts armstrong_number(370)
# The number 370 is an Armstrong number.
puts armstrong_number(10)
# The number 10 is not an Armstrong number.
puts armstrong_number(1634)
# The number 1634 is an Armstrong number.
puts armstrong_number(123)
# The number 123 is not an Armstrong number.
#
# Invalid inputs
#
puts armstrong_number("153")
# Error: Please provide number only!
puts armstrong_number("a")
# Error: Please provide number only!