Convert string to code at run time c++

问题

I am generating If Else Expressions of the following format

If(X > 10) Then Fly = True Else Fly = False
If(X > 9) Then Fly = True Else Fly = False
If(X > 8) Then Fly = True Else Fly = False
If(X > 7) Then Fly = True Else Fly = False
If(X > 6) Then Fly = True Else Fly = False

I was Wondering Can i execute this expressions at run time? I don't know if my question is clear.

I'll add an example

String = "";
for(int i = 0; i < n; i++)
{
     string ="if(x > 10){Fly = true;} else {Fly = False;}";
     Execute (Expression HERE)! 

}

Is it even possible to do it? lol Thank you. Hani.

回答1:

It is possible to use TCC ( http://bellard.org/tcc/ ). It allows to compile and run code natively at runtime. Another approach is to use an interpreter, there are plenty out there (LUA, Python etc, see list wiki).

回答2:

One does not simply interpret C/C++ code... AFAIK you just can't.
(except if you compile another binary and run it from cmd line maybe...)

Note: You can write

fly = (x > 10);

instead of

if(x > 10){
    fly = true;
}else{
    fly = false;
}

回答3:

No. C++ is a compiled language and has no eval-function or the-like. You may want to include a scripting engine into your program, like Lua

回答4:

Not unless you apply Greenspun's 10th rule.

来源：https://stackoverflow.com/questions/18766048/convert-string-to-code-at-run-time-c