Ruby program to calculate the sum of all even numbers

Ruby code to calculate the sum of all even numbers

Method 1 : Using the classical way using %2

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

sum=0

puts "Enter n:-"
n=gets.chomp.to_i

i=1
while(i<=n)
	if(i%2==0) 	#using % operator
		sum=sum+i
		i=i+1
	else
		i=i+1
	end
end

puts "The sum is #{sum}"

Output

RUN 1:
Enter n:-
5
The sum is 6

RUN 2:
Enter n:-
60
The sum is 930

Explanation:

In this program, we will calculate the sum of all even numbers up to n. We have used the remainder operator for this %. As this is division by two, then the number will return only 0 or 1 which are directly test in the if condition. n is the number up to which the check is to be performed. The variable Sum stores the sum of all the even numbers. Which is returned by the program after all numbers till n are traversed using a loop (while loop in our program).

Method 2: Using the even method that returns true if the number is even

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

sum=0

puts "Enter n:-"
n=gets.chomp.to_i

i=1
while(i<=n)
	if(i.even?) #using .even? method
		sum=sum+i
		i=i+1
	else
		i=i+1
	end
end

puts "The sum is #{sum}"

Output

Enter n:-
10
The sum is 30

Explanation:

In this program, we will calculate the sum of all even numbers up to n. We have used a Ruby method named even? to check if the number is even or not. The method returns true if the number is even. n is the number up to which the check is to be performed. The variable sum stores the sum of all the even numbers. Which is returned by the program after all numbers till n are traversed using a loop (while loop in our program).