Factorial and test unit for factorial #2

hemahg · 2019-10-03T04:32:11Z

No description provided.

hallelujah · 2019-10-04T13:00:31Z

Hema/lib/first_project/power.rb

+        return result
+      else
+      power = -1*power
+        for i in (1..power) do


Or you could have done:

1.0/pow(num, -power)

But that is fine ;)

hallelujah · 2019-10-04T13:01:33Z

Hema/lib/first_project/power.rb

+  class Power
+    def self.pow(num,power)
+      result = 1.0
+      if(power >=0)


Parenthesis are not mandatory

hallelujah · 2019-10-04T13:02:06Z

Hema/lib/first_project/power.rb

+        for i in (1..power) do
+         result = result*num
+        end
+        return result


You can return result at the end of the method

hallelujah · 2019-10-04T13:02:47Z

Hema/lib/first_project/power.rb

+        for i in (1..power) do
+          result = result*(1/num)
+        end
+        return result.round(9)


That is acceptable for the purpose of the excercise

hallelujah · 2019-10-04T13:06:43Z

Programming Foundations: Algorithms/Factorial-test/fact.rb

+       @n = @n - 1
+     end
+     result
+   end


Be wary of indentation, it makes the code more readable.
You probably want to setup your IDE with correctly.

That makes me think of a good read for start https://github.com/rubocop-hq/ruby-style-guide

hallelujah · 2019-10-04T13:07:10Z

Programming Foundations: Algorithms/Factorial-test/test_unit/Facttest.rb

+
+
+
+class Facttest < Test::Unit::TestCase


Please follow convention for file and directory namingnaming

hallelujah · 2019-10-04T13:08:26Z

Programming Foundations: Algorithms/Factorial-test/test_unit/Facttest.rb

@@ -0,0 +1,21 @@
+require "test/unit"
+require_relative "/home/hema/RoR-Learning-Path/Programming Foundations: Algorithms/Factorial-test/fact"


Do not require_relative

Rubyists generally run test with include in load path option -I. e.g: ruby -Ilib:test test/my_example_test.rb

hallelujah · 2019-10-04T13:09:00Z

Programming Foundations: Algorithms/Factorial-test/test_unit/Facttest.rb

+    assert_equal(6, Fact.new(3).fact)
+  end
+
+  def test_Zero


Follow convention see https://github.com/srijitamukherjee/RoR-Learning-Path/pull/2/files#r331490367

hallelujah · 2019-10-04T13:09:22Z

Programming Foundations: Algorithms/Factorial-test/test_unit/Facttest.rb

+    assert_equal(1, Fact.new(0).fact)
+  end
+
+  def test_negative


Make it more readable
See https://github.com/srijitamukherjee/RoR-Learning-Path/pull/2/files#r331490367

Martouta · 2019-10-14T12:23:41Z

Hema/test/power_test.rb

+require 'first_project/power'
+
+class PowerTest < TestBase
+  test 'powerofnumber' do


since the name is just a string, i think that it is easier to read like this: 😄

Suggested change

test 'powerofnumber' do

test 'power of number' do

And then when you run the test, it will convert it internally to power_of_number which is how we name methods in Ruby (this naming convention is called snake case)

Martouta · 2019-10-14T12:47:27Z

Hema/lib/first_project/power.rb

+    def self.pow(num, power)
+      result = 1
+      if power >= 0
+        for i in (1..power) do


What I am gonna say in this comment, I don't know if it is appropiate or if it is too early (too difficult at this stage), so if you find it too hard right now, do not worry and just ignore this comment 😂

In Ruby we usually write this for i in (1..power) do like (1..power).each do |i| and what it does is: for the instance (1..power) of the class Range, call its instance method each and run the block after the do with the i as the parameter of the block.

Alternatively, as you do not mind about the index at all, you can also use the instance method times of the class Integer, which you can use when either you don't care about the value of the index, or when it can start by 0.

So it would be:

power.times { result *= num }

Considering that { ... } is the same as do ... end 😄 .

You can also use inject of an Enumerable (which is mostly any object that can be iterated, like a Range or an Array for example), and then you do not need the result variable and it is shorter 😄 Although it is too inneficient for this and I wouldn't recommend it, but since this is for the sake of learning, it would be:

def self.pow(num, power) if power >= 0 ([num] * power).inject(1) { |n, result| result * n } # Or even: ([num] * power).inject(:*) || 1 else 1.0 / pow(num, -power) end end

What ([num] * power).inject(1) { |n, result| result * n } does is, first make an array of power elements, all of them containing num, and then iterate all of them, with a variable called result starting by 1, and for each iteration of the array save in that variable the value of result * num, which is what returns at the end.

And there could be also a recursive version of this method, which in code is usually simpler but you also need to check to what it does with the stack of memory 😄 This version would be:

def self.pow(num, power) if power == 0 1 elsif power > 0 num * pow(num, power - 1) else # power < 0 1.0 / pow(num, -power) end end

And there are probably more efficient versions but for now this is enough 😄

Martouta · 2019-10-14T14:18:52Z

Hema/lib/first_project/power.rb

@@ -0,0 +1,15 @@
+module Hema
+  class Power


We spoke in private before but I rather put it here as well.
We don't usually create a class if we don't expect it to be ever instantiate it and for that we usually just make a module instead. Like this:

module Hema module Power def pow(...) ... end end end

And from outside called like: Hema::Power.pow(...)

hallelujah

Implementation is good.

Now all comments are about Styling and using Ruby Core Library methods

hallelujah · 2019-10-15T06:41:47Z

Programming Foundations: Algorithms/Factorial_test/lib/fact.rb

+    end
+
+    def fact
+      if @n == 0


We try to avoid many nested if for learning you have https://rubystyle.guide

You can also use rubocop to tell you what is bad styling in your code https://github.com/rubocop-hq/rubocop

hallelujah · 2019-10-15T06:44:25Z

Programming Foundations: Algorithms/Factorial_test/lib/fact.rb

+        raise 'negatives are not acceptable'
+      else
+        result = 1
+        while @n > 0


As stateed by @Martouta, when you have Enumerable, try to read the docs and use some of the methods of this module.

Try to understand this simpler version is:

(1..n).inject(&:*)

hallelujah · 2019-10-15T06:45:02Z

Programming Foundations: Algorithms/Factorial_test/test/Fact_test.rb

+
+  def test_negative
+    Factorial_test::Fact.new(-5).fact
+    assert_raise do


This does not work as you do not execute nothing inside the block.

hallelujah · 2019-10-15T06:45:39Z

Hema/test/power_test.rb

+class PowerTest < TestBase
+  test 'powerofnumber' do
+		assert_equal 4, Hema::Power.pow(2, 2)
+		assert_equal 1, Hema::Power.pow(2.0, 0)


There are formatting/styling issues, see https://rubystyle.guide

hema added 10 commits September 26, 2019 18:38

Added file

2c75cc2

Added file to ruby basics

c90f244

Pattern program

264c74e

Added test-unit

055d8c1

Removed Facttest.rb file

659e4bc

Factorail and factorial test_unit

fe46453

Updating branch

5277bc9

Creating floder structure of the project

2088001

Creating unit test for power.rb

d5e66d1

Implementing logic to find the power of number

c25f5e3

hallelujah reviewed Oct 4, 2019

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Hema/lib/first_project/power.rb Outdated

class Power

def self.pow(num,power)

result = 1.0

if(power >=0)

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hallelujah Oct 4, 2019

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Parenthesis are not mandatory

hallelujah reviewed Oct 4, 2019

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Martouta reviewed Oct 14, 2019

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hallelujah reviewed Oct 15, 2019

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Updated factorial test

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Factorial and test unit for factorial #2

Factorial and test unit for factorial #2

hemahg commented Oct 3, 2019

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hallelujah Oct 15, 2019

		@@ -0,0 +1,21 @@
		require "test/unit"
		require_relative "/home/hema/RoR-Learning-Path/Programming Foundations: Algorithms/Factorial-test/fact"

Factorial and test unit for factorial #2

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Factorial and test unit for factorial #2

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