Class: List

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/prct06/list.rb

Instance Method Summary collapse

Constructor Details

#initialize ⇒ List

Returns a new instance of List.



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# File 'lib/prct06/list.rb', line 20

def initialize
  @head = nil
  @tail = nil
end

Instance Method Details

#add(value) ⇒ Object 



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# File 'lib/prct06/list.rb', line 32

def add(value)
  node = Node.new(value, nil, nil)
  if @head == nil
    @head = node
  end
  if @tail != nil
    @tail.nex = node
    node.prev = @tail
  end
  @tail = node
  return self
end

#each(&block) ⇒ Object 



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# File 'lib/prct06/list.rb', line 89

def each(&block)
  to_array.each(&block)  
end

#head ⇒ Object 



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# File 'lib/prct06/list.rb', line 25

def head
  @head
end

#pop ⇒ Object 



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# File 'lib/prct06/list.rb', line 62

def pop
  if @tail != nil
    if @tail.prev != nil
      toReturn = @tail
      @tail = @tail.prev
      @tail.nex = nil
      return toReturn
    else
      lastElement = @tail
      @tail = nil
      return lastElement
    end
  else
    return "List is empty" 
  end
end

#shift ⇒ Object 



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# File 'lib/prct06/list.rb', line 45

def shift
  if @head != nil
    if @head.nex != nil
      toReturn = @head
      @head = @head.nex
      @head.prev = nil
      return toReturn
    else
      lastElement = @head
      @head = nil
      return lastElement
    end
  else
    return "List is empty"
  end
end

#tail ⇒ Object 



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# File 'lib/prct06/list.rb', line 28

def tail
  @tail
end

#to_array ⇒ Object 



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# File 'lib/prct06/list.rb', line 79

def to_array
  resultArray = []
  current = @head
  while current != nil do
    resultArray << current
    current = current.nex
  end
  return resultArray
end