一个字符串转换在C线code的 [英] Converting a string to a line of code in C

问题描述

我试图找到一种方法将字符串转换到我的code的线。

I am trying to find a way to convert a string to the lines of my code.

例如，我想尝试成才这样的：

For example, i want to try someting like this:

int x=3;
char str[80];
gets(str);  // Assuming the user gives input: "x + 3"
y = str;
printf("%d",y); // Output: "6" (3 + 3)

因此​​，该程序输出6（3 + 3）。
我想这对于建立一个函数绘图仪..但在这里我卡住，无法找到任何办法。请你告诉我一个方法将这些字符串转换为code线？

So that this program outputs "6" (3+3). I want to this for building a function plotter.. But here I get stuck and can't find any way. Would you please show me a way to convert these strings to lines of code?

推荐答案

您想要做的是什么前pression评价即可。我建议2种方法这或许有助于你更接近预期的解决方案。

What you want to do is expression evaluation. I suggest 2 methods which perhaps help you to get closer to the expected solution.

1. 评估前pression用二叉树：构建树至极重presents除权pression和运营商之间的precedence。

1. Evaluate the expression with a binary tree: build a tree wich represents the expression and the precedence among the operators.

可能有人如上所述。波兰的形式，基于堆栈的评价。首先构建一个堆栈原来前pression的抛光形式，而且比再次评估波兰形式与栈。而最后：使用谷歌与这些keywoards：）

May be it was mentioned above. Polish-form, stack-based evaluation. First build the polish-form of the original expression with a stack, and than evaluate the polish-form with a stack again. And the last: use google with these keywoards :)

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