Reputation: 19

Get sum of numbers within range (from 0 to user input)

This is the code i am using, its purpose is for the user to enter an integer, the program will then take the sum of all the numbers up to and including the one entered. There is probable an easier way to do this

 sum = 0
 puts "please enter a number"
 counter = gets.chomp.to_i
 begin
  sum += counter
  counter -= 1
 end while counter == 0

Upvotes: 1

Answers (5)

szsoppa

Reputation: 113

As I understand you are trying to sum elements of range. Giving number 3, you want to get sum which is 6.

One way (time consuming) is to use inject or sum. You can try following:

1. [*1..value].sum
2. [*1..value].inject(:+)

The other (recommended), very efficient way is to use this equation:

(value + 1) * (value) / 2

Upvotes: 0

potashin

Reputation: 44601

The issue with your code is in counter == 0 condition in your loop, since it runs only once and then if count is not equal to 0 (in other words, if user's input wasn't 1), it stops. You not only can make this without using loops, you can shorten the whole process:

counter = gets.to_i
sum = (0..counter).inject(:+)

Demo

P.S. As you could have noticed, you can omit .chomp when you are using .to_i.

Upvotes: 1

Bhatiya J

Reputation: 126

If I understood you correctly, you could try something like this...

puts "Please enter a positive number..."
number = gets.chomp.to_i

puts "Sum of all numbers is: #{ (1..number).inject { |sum, n| sum + n} }"

I'm using enumerable method 'inject' to sum up the total. Learn more about 'inject' method at http://ruby-doc.org/core-2.2.2/Enumerable.html#method-i-inject.

Hope this helps!

Upvotes: 0