Ruby program to calculate the sum of all odd numbers up to N

=begin
Ruby program to calculate sum of 
all odd numbers upto n
=end

sum=0

puts "Enter n: "
n=gets.chomp.to_i
i=1
while(i<=n)
    if(i%2!=0)
        sum=sum+i
        i=i+1
    else
        i=i+1
    end
end

puts "The sum is #{sum}"

Output:

RUN 1:
Enter n:
10
The sum is 25

RUN 2:
Enter n:
5
The sum is 9