Class: Lista

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

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Lista

Constructor

Parameters:

  • val —

    as first element



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# File 'lib/pract/list.rb', line 9

def initialize
  @head = @tail = nil
end

Instance Attribute Details

#head ⇒ Object

Returns the value of attribute head.



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# File 'lib/pract/list.rb', line 5

def head
  @head
end

#tail ⇒ Object

Returns the value of attribute tail.



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# File 'lib/pract/list.rb', line 5

def tail
  @tail
end

Instance Method Details

#add_first(val) ⇒ Object

Add val as first element



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# File 'lib/pract/list.rb', line 39

def add_first (val)
  if (@head!= nil)
    point = @head
    point.prev = Nodo.new(nil, val, point)
    @head = point.prev
  else
    @head = @tail = Nodo.new(nil, val, nil)
  end
end

#add_last(val) ⇒ Object

Add val as last element



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# File 'lib/pract/list.rb', line 29

def add_last (val)
   if (@head!= nil)
    point = @tail
    point.next = Nodo.new(point, val, nil)
    @tail = point.next
  else
    @head = @tail = Nodo.new(nil, val, nil)
  end
end

#each {|point.val| ... } ⇒ Object

Make list enumerable

Yields:

  • (point.val) 


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# File 'lib/pract/list.rb', line 114

def each
  point = @head
  while(point != @tail) do
    yield point.val
    point = point.next
  end
  yield(point.val)
end

#remove(val) ⇒ Object

Remove an element

Parameters:

  • val (value) —

    as the value we want to remove



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# File 'lib/pract/list.rb', line 60

def remove (val)
  if (@head != nil)
      if(@head == @tail) && (@head.val == val)
      @head = nil
      @tail = nil
    elsif (@head.val == val)
      remove_first
    elsif (@tail.val == val)
      remove_last
    else
      point = @head
      while (point.next != nil) && (point.val != val)
        point = point.next
      end
      if point != @tail
        before = point.prev
        after = point.next
        before.next = after
        after.prev = before
        point.prev = nil
        point.next = nil
      end
    end
  end
end

#remove_first ⇒ Object

Remove the first element



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# File 'lib/pract/list.rb', line 49

def remove_first
  point = @head
  @head = point.next
end

#remove_last ⇒ Object

Remove the last element



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# File 'lib/pract/list.rb', line 54

def remove_last
  point = @tail
  @tail = point.prev
end

#search(val) ⇒ Object

Returns position of val[from 1] or nil is not found.

Returns:

  • position of val[from 1] or nil is not found



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# File 'lib/pract/list.rb', line 97

def search(val)
  num = 1
  point = @head
  while(point != @tail)
    if(point.val == val)
      return num
    else
      num = num+1
      point = point.next
    end
  end
  if @tail.val == val
    return num
  else return 0
  end
end

#sz ⇒ Object

Returns size of element.

Returns:

  • size of element



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# File 'lib/pract/list.rb', line 86

def sz
  size_list = 0
  point = @head
  while(point != tail)
    size_list = size_list + 1
    point = point.next
  end
  size_list = size_list+1
  return size_list
end

#to_s ⇒ Object

Returns string format.

Parameters:

  • point —

    as auxiliar pointer

  • elements —

    as showing variable

Returns:

  • string format



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# File 'lib/pract/list.rb', line 15

def to_s
  elements = "["
  point = @head
    while point != @tail
      elements = elements + point.val.to_s
        elements = elements + "], ["
      point = point.next
    end
  if (@head != nil)
    elements = elements + point.val.to_s
  end
  elements = elements + "]"
end