- 60 名前：名前は開発中のものです。 mailto:sage [02/06/29 23:23 ID:???]
- とりあえずここまで… 残りは後で考えます
#! /usr/bin/env ruby
def infix_to_postfix(expr)
stack = ['(']
result = []
operator_priority = {
'*' => 50, '/' => 50,
'+' => 20, '-' => 20,
'(' => 10, ')' => 10,
}
expr.each{ |x|
if '+ - * /'.split.include?(x)
# operator
while operator_priority[stack.last] >= operator_priority[x]
result.push(stack.pop)
end
stack.push(x)
else
result.push(x) # operand はそのまま出力
end
}
while not stack.empty? and operator_priority[stack.last] >= operator_priority[')']
result.push(stack.pop)
end
result.pop # 最後は'('が入ってるので捨てる
result
end
puts infix_to_postfix(ARGV[0].split).join
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