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