TheAlgorithms-Ruby/data_structures/stacks/stack.rb
2020-12-27 14:07:08 -08:00

87 lines
1.4 KiB
Ruby

# A stack is an abstract data type that serves as a collection of
# elements with two principal operations: push() and pop(). push() adds an
# element to the top of the stack, and pop() removes an element from the top
# of a stack. The order in which elements come off of a stack are
# Last In, First Out (LIFO)
class StackOverflowError < StandardError; end
class Stack
def initialize(limit, stack = [])
@stack = stack
@limit = limit
end
attr_accessor :stack, :limit
def push(item)
raise StackOverflowError unless stack.count < limit
stack << item
end
def pop
stack.pop
end
def peek
stack.last
end
def empty?
stack.count.zero?
end
def full?
stack.count == limit
end
def size
stack.count
end
def contains?(item)
stack.include?(item)
end
end
stack = Stack.new(10, [])
puts stack.empty?
# => true
stack.push(3)
stack.push(5)
stack.push(7)
stack.push(9)
puts stack.full?
# => false
puts stack.contains?(5)
# => true
puts stack.pop
# => 9
puts stack.peek
# => 7
puts stack.size
# => 3
puts stack.inspect
# => #<Stack:0x00007fceed83eb40 @stack=[3, 5, 7], @limit=10>
stack.push(13)
stack.push(15)
stack.push(17)
stack.push(19)
stack.push(23)
stack.push(25)
stack.push(27)
# At this point, the stack is full
stack.push(29)
# => data_structures/stacks/stack.rb:18:in `push': StackOverflowError (StackOverflowError)
# from data_structures/stacks/stack.rb:83:in `<main>'