# Ruby Blocks – HackerRank Solution

In this post, we will solve Ruby Blocks HackerRank Solution. This problem (Ruby Blocks) is a part of HackerRank Ruby series.

## Problem

Higher order functions are one of the key components of functional programming.

A higher order function is a tool that takes other functions as parameters or returns them as a result.

Blocks are nameless methods that can be passed to another method as a parameter.
Passing a block to a method is a great way of data abstraction.

Blocks can either be defined with a keyword `do ... end` or curly braces `{ ... }`.

Example:

a). Passing a block to a method that takes no parameter

CODE

``````def call_block
puts "Start of method."
yield
puts "End of method."
end
call_block do
puts "I am inside call_block method."
end``````

OUTPUT

``````Start of method.
I am inside call_block method.
End of method.``````

In this example, a block is passed to the call_block method.
To invoke this block inside the method, we used a keyword, `yield`.
Calling `yield` will execute the code within the block that is provided to the method.

b). Passing a block to a method that takes one or more parameters.

CODE

``````def calculate(a,b)
yield(a, b)
end

puts calculate(15, 10) {|a, b| a - b}   ``````

OUTPUT

``5``

In this example, we have defined a methodÂ calculateÂ that takes two parametersÂ aÂ andÂ b.
TheÂ `yield`Â statement invokes the block with parametersÂ aÂ andÂ b, and executes it.

Task

You are given a partially complete code. Your task is to fill in the blanks (`_______`).
The factorial method computes:Â `n!`Â {Â nÂ xÂ n – 1Â xÂ . . . 2Â xÂ 1Â }.

## Solution – Ruby Blocks – HackerRank Solution

```def factorial
yield
end

n = gets.to_i
factorial do
puts (1..n).inject(:*)
end
```

Note: This problem (Ruby Blocks) is generated by HackerRank but the solution is provided by CodingBroz. This tutorial is only for Educational and Learning purpose.