Write a program in ruby to find factorial of a number

By: Prof. Dr. Fazal Rehman | Last updated: February 3, 2024

I am sharing with you a program in Ruby to find the factorial of a number:

ruby

def factorial(n)

if n == 0

1

else

n * factorial(n-1)

end

end

 

puts “Enter a number to find its factorial:”

number = gets.chomp.to_i

 

result = factorial(number)

 

puts “Factorial of #{number} is #{result}.”

Step 1: define a method “factorial” with an integer n as its argument.

Step 2: The method “factorial”  checks if n is 0, then returns 1, because the factorial of 0 is 1. Otherwise, it recursively calls itself with n-1 as its argument, multiplying the result by n at each level until n reaches 0.

Step 3: ask the user to input a number with the help of puts

Step 4: convert the number to an integer using to_i and store it in a variable “number”

Step 5: call the factorial method with the number as its argument, and output the result.