如何从 C 源文件中删除所有/* */注释? [英] How can I delete all /* */ comments from a C source file?

问题描述

我有一个从别处复制的 C 文件，但它有很多如下注释:

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++)

如何删除/* 和*/ 括起来的所有注释.有时候，评论由 4-5 行组成，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 */ 之间的所有文本，甚至 也可以介于两者之间.请使用 sed、awk 或 perl 之一帮助我做到这一点.

Basically, I need to delete all text between /* and */ and even 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 预处理器来执行此操作?你为什么要把自己局限在一个本土的正则表达式中?

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

[Edit] 这种方法也可以干净地处理 Barts printf(".../*...") 场景

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

示例:

[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并压缩所有内容

Or you can remove the whitespace and condense everything

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

重新发明轮子没有用，是吗?

No use re-inventing the wheel, is there?

如果您想不通过这种方法扩展包含的文件和宏，cpp 为此提供了标志.考虑:

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

有一个警告，可以避免宏扩展，但宏的原始定义已从源代码中剥离.

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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