Method: List#tail

Defined in:
lib/nutrientes/list.rb,
lib/nutrientes/list.rb

#tail ⇒ Object (readonly)

Returns The last element of the list.

Returns:

  • (Object) —

    The last element of the list



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# File 'lib/nutrientes/list.rb', line 31

class List
    attr_reader :head, :tail, :size
    include Enumerable
    
    #   Initialization of the list
    def initialize()
        @size = 0
        @head = nil
        @tail = nil
    end
    
    # Defines the each method to make use of the Enumerable module
    def each
        actual = @head
        while actual != nil do
            yield actual
            actual = actual.nodo[:next_]
        end
    end
    
    # Inserts a node at the beginning of the list
    # @param [Object] nodo node to insert
    # @return nil
    def push(nodo) 
        if @size == 0 then
            @head = nodo
            @tail = nodo
        else
            @tail.nodo[:next_] = nodo
            nodo.nodo[:prev_] = @tail
            @tail = nodo
        end
        @size += 1
    end
    
    # Inserts a node at the end of the list
    # @param nodo [Object] node to insert
    # @return nil
    def insert(nodo)
        if @size == 0 then
            @head = nodo
            @tail = nodo
        else
            @head.nodo[:prev_] = nodo
            nodo.nodo[:next_] = @head
            @head = nodo
        end
        @size += 1
    end
    
    # Deletes a node from the beginning of the list
    # @return nil
    def truncate
        if size > 1
            @head = @head.nodo[:next_]
            @head.nodo[:prev_] = nil
            @size -= 1
        elsif size == 1
            @head = nil
            @tail = nil
            @size -= 1
        end
    end
    
    # Deletes a node from the end of the list
    # @return nil
    def pop
        if size > 1
            @tail = @tail.nodo[:prev_]
            @tail.nodo[:next_] = nil
            @size -= 1
        elsif size == 1
            @tail = nil
            @head = nil
            @size -= 1
        end
    end
end