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Please answer these questions for me:
Q1: Write a method, pow, that takes two (non-negative, integer) numbers, base and exponent and returns base raised to the exponent power. (No fair using Ruby's base ** exponent notation!).
Q2: Write a method, sum which takes an array of numbers and returns the sum of the numbers.
Q3: Write a method, is_prime?, that takes a number num and returns true if it is prime and false otherwise.
You may wish to use the modulo operation: 5 % 2 returns the remainder when dividing 5 by 2: 1. If num is divisible by i, then num % i == 0. (You would not be expected to already know about modulo for the challenge)
Q4: Using your is_prime? method, write a new method, primes that takes a (non-negative, integer) number max and returns an array of all prime numbers less than max.
I am interested in the simplest solutions. If you could include step by step explanations that would be great.

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Last Post by Herve_1
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I am interested in the simplest solutions. If you could include step by step explanations that would be great.

@Herve_1

My question is how did you came up with these questions.

It's more related to school.

What book do you have? It should have an examle of that.

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Hi,

There is no simplest form of a solution to a problem, without going into the basics.

I never crossed past the PHP forum, but I just did this time. It is not that I am not capable of writing codes in Ruby, but it is because I am so darn lazy.

My question is, what good will it brings you, if I or someone ever give you the codes that will satisfy your school homework questions?

Here are the stages of Ruby that I have to go through, while learning the language. Believe me it is not that hard really... at least for me. I just have to remind me about all these things.

  1. Learn the form formatter.

    print "What's your name?"
    first_name = gets.chomp

  2. Learn the operators like so..

    Addition (+)
    Subtraction (-)
    Multiplication (*)
    Division (/)
    Exponentiation (**)
    Modulo (%)

to multiply

1 * 2

to add

1 + 2

to exponentiate

2 ** 2
  1. Learn sring function . Remember pretty much everything in Ruby are objects.

to get the length of a string

"mystring".length

"mystring".upcase

# this will create a  lower case of MYSTRING
"MYSTRING".downcase
  1. Learn the naming conventions

    my_localvariable = "hello Ruby"

    this is legal in Ruby, but you must stay within the norms

    @my_localvariables = "hello Ruby"

  2. Master the control flow as you move along

    print "Type a number: "
    num_typed = Integer(gets.chomp)

    if num_typed > 0
    puts "you just typed an positive integer"

    elseif num_type < 0
    puts "you just type a negative integer"

    else

    puts "it is nada, zip, zero"

    end

  3. Learn what is unique in Ruby than other languages.. for example unless.

    submitted = false

    unless submitted
    puts " I ain't gonna let you go"

  4. Learn comparison

    think_twice = 6 != 20
    what_about = 3 == 20

    less than or equal to something

    this_integer = 3 <= 5
    how_about = 3 >= 2

  5. Know your Boolean operators. This is pretty important in programming. OR, AND, NOT

    || && !

    example will return an boolean true

    give_boolean = 52 == 25 && 42 == 16

    1. Learn all the loops while, until, for. Learn iterators block

    2. Learn Methods , Sorting and Blocks. This applies to your questions

      def makeCube(n)
      puts n ** 3
      end

      makeCube(4)

  6. Learn how to write Object Oriented in Ruby

Bonus: One of your question has been answered.. what a luck huh?

def determine(numberX)

  puts "Not an Integer." unless n.is_a? Integer

  is_prime = true
  for x in 2..numberX-1

    if numberX % x == 0
      is_prime = false

    end
  end

  if is_prime
    puts "#{numberX} yes, it is a prime number!"
  else
    puts "#{numberX} is not a prime number."
  end
end

to test the function above... try ..

prime(51)
prime(11)

that should give you an output of : 51 is not a prime number, and 11 yes, it is a prime number!.

Lastly, read your books..

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thank you for your input.

it was not for a homework. the questions were in prepparation for a few other questions.
However thank you!!!

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