Ocaml Hello World! 

Ocaml Hello World! 


Click on RUN button to see the output

OCaml Online Compiler

Write, Run & Share OCaml code online using OneCompiler's OCaml online compiler for free. It's one of the robust, feature-rich online compilers for OCaml language, running on the latest version 4. Getting started with the OneCompiler's OCaml compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as OCaml. OneCompiler also has reference programs, where you can look for the sampleprograms and start learning. Happy learning!!

About OCaml

OCaml is general purpose programming language with more importance to safety and expressiveness. With it's advanced type system, it helps to catch the mistakes in an efficient way. Hence this is used to develop applications/environments where a single mistake can cost millions and speed matters. It has good community support and rich set of development tools and libraries.

key features

  • Strongly typed functional language
  • Easy to learn
  • Very powerful type system
  • Automatic memory management
  • There is a seperate compilation of standalone applications.
  • Ocaml compiler can also produce machine codes
  • Multiple inheritance and parametric classes etc can be expressed in a simpler way
  • User can define algebraic data types

Data types

ClassificationData types
Basic data typesintegers, floating point numbers, booleans, characters, strings
Sophisticated data typestuples, arrays, lists, sets, hash tables, queues, stacks, data streams


OCaml allows users to define new data types.


Variable is a name given to the storage area in order to manipulate them in our programs.

let varible-names = value


1. If:

If is performed when you need to choose expression based on a boolean-condition.

if boolean-condition then (* code if condition is true *)
if boolean-condition then (* code if condition is true*) else (* code if condition is false*)

2. While:

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

while boolean-condition do
  (* code *)

3. For:

For loop is used to iterate a set of statements for specific number of items.

for var = start-value to end-value do
  (* code *)
for var = start-value downto end-value do
  (* code *)