难以理解如何处理调车场算法的输出 [英] Trouble understanding what to do with output of shunting-yard algorithm

问题描述

我一直在查看Wiki页面： http://en.wikipedia.org/ wiki / Shunting-yard_algorithm

I've been looking at the wiki page: http://en.wikipedia.org/wiki/Shunting-yard_algorithm

我已经使用代码示例构建了第一部分，基本上我现在可以打开：

I've used the code example to build the first part, basically I can currently turn :

3 + 4 * 2 /（1-5）^ 2 ^ 3 到 3 4 2 * 1 5- 2 3 ^ ^ / +

但是我不知道该如何使用 3 4 2 * 1 5 − 2 3 ^ ^ / + 获得 3.00012207

But I don't know how to then use 3 4 2 * 1 5 − 2 3 ^ ^ / + to obtain 3.00012207

以及示例代码和

有人可以解释如何评估 3 4 2 * 1 5 − 2 3 ^ ^ / + 并给出答案。提前致谢。我不需要代码示例，只是一个很好的解释或示例细分。

Could someone please explain how to evaluate 3 4 2 * 1 5 − 2 3 ^ ^ / + and produce the answer. Thanks in advance. I don't need a code example just a good explanation or a breakdown of an example.

这没关系，但我正在使用.net C＃。

Not that it matters but I am working .net C#.

推荐答案

调车场算法的目的是其输出位于反向波兰符号，它很容易评估：

The purpose of the shunting yard algorithm is that its output is in Reverse Polish Notation, which is straightforward to evaluate:

• 创建一个堆栈来保存值


• 同时还有反向抛光符号输入：
  
  
  
  • 读取输入项
  
  
  • 如果它是一个值，则将其压入堆栈
  
  
  • 否则，它是一个操作；从堆栈中弹出值，对这些值执行操作，将结果推回
  
  
  • create a stack to hold values
  • while there is reverse polish notation input left:
    • read an item of input
    • if it is a value, push it onto the stack
    • otherwise, it is an operation; pop values from the stack, perform the operation on those values, push the result back

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