Ruby program to check whether the given number is prime or not

=begin 
Ruby program to check whether the given number is 
prime or not.
=end

puts "Enter the number:"
num=gets.chomp.to_i
count=0
if (num==0)
    puts "0 is not prime"
else
    
    i=2
    while(i<num)
        if (num%i==0)
            count+=1
        end
        i+=1
    end
    
end
    if count>1
        puts "#{num} is not a prime number"
    else
        puts "#{num} is a prime number"
    end

Output:

RUN 1 : 
Enter the number:
13
13 is a prime number

RUN 2:
Enter the number:
890
890 is not a prime number