puts "Hello, World!" 

Ruby Online Compiler

Write, Run & Share Ruby code online using OneCompiler's Ruby online compiler for free. It's one of the robust, feature-rich online compilers for Ruby language, running on the latest version 2.3.1. Getting started with the OneCompiler's Ruby compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as Ruby and start coding.

Read input from STDIN in Ruby

OneCompiler's Ruby online editor supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample Ruby program which takes name as input and prints hello message with your name.

name = gets.chomp               
print "Hello #{name}.\n" 

About Ruby

Ruby is a general purpose object oriented programming language developed by Yukihiro Matsumoto.

Key features

  • More commonly used in Rails applications.
  • Concise and simple to read and powerful too.
  • Open-source
  • Expressive features and visual appearance
  • Flexible language

Syntax help

Data types

Data typeDescriptionUsage
FixnumRepresents normal numbersx = 10
BignumRepresents big numbersx =9999999999
FloatRepresents decimal numbersx = 3.14
ComplexRepresents imaginary numbersx = 1 + 2i
RationalRepresents fractional numbersx = 1/4
BigDecimalRepresents precision decimal numbersx=1.0
HashRepresents key value pairs{"Website"=>"onecompiler","message" => "Happy learning"}


In Ruby, there is no need to explicitly declare variables to reserve memory space. When you assign a value to a variable, declaration happens automatically and a prefix is needed to indicate the following variable types.

Variable typeDescription
Local variablesScope is limited to the block of the variable initialization. Variable name must start with either _ or lowercase letter.
Class variablesClass variables belongs to whole class and can be accessible anywhere inside the class. Variable name must start with @@. They must be initialized before use.
Instance variablesInstance variables belongs to a instance of the class. They can be accessed from any instance of the class within a method. Variable name must start @
Global variablesScope is global and hence they can be accessible anywhere in the program. Variable name must start with $

Loops and conditional statements

1. If family:

If, If-else, Nested-Ifs are used when you want to perform a certain set of operations based on conditional expressions.




    #code if condition is true  
    #code if condition is false  


    #code if above condition is true  
    #code if above condition is true  
    #code if above condition is true  
    #code if all the conditions are false  

2. Case:

Case is similar to Switch statement, where it is used to execute one set of a statement from multiple conditions.

case expression  
[when expression [, expression ...] [then]  
   # code ]...  
   # code ]  

3. For:

For loop is used to iterate a set of statements based on a condition.

for variable in expression do   
  # code  

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while condition do   
 # code 

5. Do-while:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

loop do   
  break if conditional-expression