C - 带操作数的算法 [英] C - algorithm with operands

问题描述

Hello,

I have an issue, i have a string, e.g: `"!!!T&(!F)"` and i want those operations to be executed and the output should be in a variable which i will show in console.

Any idea how could i do that??
T = true ( a constant defined by me ) 
F = false ( same as T )
R = result ( the variable where i want the output)

< br $> b $ b

我尝试过的事情：



好​​吧，我陷入困境这一点，我不知道我该如何接近它。我在等待建议，解决方法..

What I have tried:

Well, i'm stuck in this point, i do not know how i should approach it. I'm waiting for suggestions, ways of solving it..

推荐答案

你要做的是评估一个逻辑表达式。 为了做到这一点，你应该首先为你想要解析的表达式系列定义一个简单的语法（你的例子只是一个这样的表达式），然后从输入字符串构建一个解析树，或者至少转换为你在RPN中的中缀表达式（反向波兰表示法）。 一旦你完成了，你可以使用一个简单的堆栈机器来执行表达式的RPN形式。



如果这对你没有任何意义，你已经咬过的东西超过了你可以咀嚼的（现在），我建议阅读Dijkstra的 Shunting-yard算法 [ ^ ]。  ;一旦你了解它是如何工作的，就不那么难了。



/ ravi

What you are trying to do is evaluate a logical expression.  In order to do this, you should first define a simple grammar for the family of expressions you want to be able to parse (your example is just one such expression), then build a parse tree from the input string, or at least convert the infix expression you have into RPN (Reverse Polish Notation).  Once you've done that, you can use a simple stack machine to execute the RPN form of the expression.

If this doesn't make any sense to you, you've bitten off more than you can chew (for now) and I suggest reading up on Dijkstra's Shunting-yard algorithm[^].  It's not that hard once you understand how it works.

/ravi

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