如何删除从C源文件中的所有/ * * /注释吗？ [英] How can I delete all /* */ comments from a C source file?

问题描述

我有我从别的地方复制了C文件，但它有很多的类似下面的评论：

I have a C file which I copied from somewhere else, but it has a lot of comments like below:

int matrix[20];
/* generate data */
for (index = 0 ;index < 20; index++)
matrix[index] = index + 1;
/* print original data */
for (index = 0; index < 5 ;index++)

我怎样可以删除 / * 和包围的所有注释* / 。有时，意见
是由4-5行，我需要删除所有这些行。

How can I delete all the comments enclosed by /* and */. Sometimes, the comments are consist of 4-5 lines, and i need to delete all those lines.

基本上，我需要删除 / * 和 * / ，甚至 \\ n 可以进来的。请帮我做到这一点使用 SED ， AWK 中的一个或 perl的。

Basically, I need to delete all text between /* and */ and even \n can come in between. Please help me do this using one of sed, awk or perl.

推荐答案

为什么不直接使用C preprocessor做到这一点？你为什么要限制自己一个土生土长的正则表达式？

Why not just use the c preprocessor to do this? Why are you confining yourself to a home-grown regex?

这种方法还可以处理的Barts 的printf（... / * ...）情景干净

This approach also handles Barts printf(".../*...") scenario cleanly

例如：

[File: t.c]
/* This is a comment */
int main () {
    /* 
     * This
     * is 
     * a
     * multiline
     * comment
     */
    int f = 42;
    /*
     * More comments
     */
    return 0;
}

$ cpp -P t.c
int main () {







    int f = 42;



    return 0;
}

或者，您可以删除空格和凝聚一切

Or you can remove the whitespace and condense everything

$ cpp -P t.c | egrep -v "^[ \t]*$"
int main () {
    int f = 42;
    return 0;
}

没有使用重新发明轮子，有没有？

No use re-inventing the wheel, is there?

如果你想的不的通过这种方式扩大包含的文件和macroa， CPP 提供标志这一点。试想一下：

If you want to not expand included files and macroa by this approach, cpp provides flags for this. Consider:

[文件：T.C]

#include <stdio.h>
int main () {
    int f = 42;
    printf("   /*  ");
    printf("   */  ");
    return 0;
}

$ cpp -P -fpreprocessed t.c | grep -v "^[ \t]*$"
#include <stdio.h>
int main () {
    int f = 42;
    printf("   /*  ");
    printf("   */  ");
    return 0;
}

有是的可避免在宏扩展轻微的警告，但宏的原始定义是从源头上剥离。

There is a slight caveat in that macro expansion can be avoided, but the original definition of the macro is stripped from the source.

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