c - 多个命令行参数 - 替换单词

Question

我有一个程序，它从命令行参数中获取任意数量的单词，并将它们替换为单词“CENSORED”。我终于让程序处理传入的第一个参数，但我无法让程序审查仅以单个字符串输出的所有参数。该程序而是根据给定的参数单独运行，并且不会将它们全部考虑在内。我该如何修改这个？

如何集中使用/操作多个命令行参数？

我的代码如下。

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

char *replace_str(char *str, char *orig, char *rep, int j, int argc)
{
    static char buffer[4096];
    char *p;

    for ( j = 1; j <= argc; j++ )  
    {

        if(!(p = strstr(str, orig)))  // Check if 'orig' is not in 'str'
        {
            if ( j == argc )    {  return str;  }  // return str once final argument is reached
            else                {  continue;    }  // restart loop with next argument
        }

        strncpy(buffer, str, p-str);  // Copy characters from 'str' start to 'orig' str
        buffer[p-str] = '\0';

        if ( j == argc )        {  return buffer;  }
        else                    {  continue;       }
    }
    sprintf(buffer+(p-str), "%s%s", rep, p+strlen(orig));
}

int main( int argc, char* argv[] )  //argv: list of arguments; array of char pointers //argc: # of arguments.
{   
    long unsigned int c, i = 0, j = 1;

    char str[4096];

    while ( (c = getchar()) != EOF )
    {
        str[i] = c;  // save input string to variable 'str'
        i++;
    }
    puts(replace_str( str, argv[j], "CENSORED", j, argc ) );

    return 0;
}


i.e. 
$ cat Hello.txt 

Hello, I am me.

$ ./replace Hello me < Hello.txt

CENSORED, I am CENSORED.

Answer 1

有两个问题，您不能保证以 null 结尾的 str，其次，您没有迭代命令行上的单词来审查每个单词。在 getchar() 循环之后在 main 中尝试以下操作:

/* null-terminate str */
str[i] = 0;

/* you must check each command line word (i.e. argv[j]) */
for (j = 1; j < argc; j++)
{
    puts(replace_str( str, argv[j], "CENSORED", j, argc ) );
}

注意:这会将每个 CENSORED 单词放在单独的行上。如注释中所述，将 puts (或者最好是 printf)移到循环之外以保持在单行上。

<小时/>

编辑

我道歉。您遇到的问题比上面提到的还要多。尝试检查修复后，很明显，根据在命令行上输入坏单词的顺序，您将继续难以解析单词。

虽然可以通过指针算术来复制/扩展/收缩原始字符串，而不管单词在命令行上出现的顺序如何，但简单地将提供的单词分离到数组中，然后进行比较要容易得多每个坏词与原始字符串中的每个词相对应。

使用 strtok 或 strsep 可以相对轻松地完成此操作。我整理了一个简单的示例来展示这种方法。 (注意:在传递给 strtok 之前复制字符串，因为它会改变原始字符串)。我相信这就是您试图做的事情，但您却没有能力比较每个单词(因此您使用 strstr 来测试匹配)。

查看示例，如果您还有其他问题，请告诉我。注意:我用 SMAX 定义替换了硬编码的 4096，并为在命令行输入的单词提供了单词最大值 WMAX。另外始终初始化字符串/缓冲区。它将使您始终能够轻松找到缓冲区中的最后一个字符，并确保缓冲区始终以空终止。

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define SMAX 4096
#define WMAX 50

char *replace_str (char *str, char **bad, char *rep)
{
    static char buffer[SMAX] = {0};
    char *p = buffer;
    char *wp = NULL;
    unsigned i = 0;
    unsigned char censored = 0;

    char *str2 = strdup (str);              /* make copy of string for strtok  */
    char *savp = str2;                      /* and save start address to free   */

    if (!(wp = strtok (str2, " ")))         /* get first word in string or bail */
    {
        if (savp) free (savp);        
        return str;
    }

    while (bad[i])                          /* test against each bad word       */
    {
        if (strcmp (wp, bad[i++]) == 0)     /* if matched, copy rep to buffer   */
        {
            memcpy (buffer, rep, strlen (rep));
            censored = 1;
        }
    }

    if (!censored)                          /* if no match, copy original word  */
        memcpy (buffer, wp, strlen (wp));

    while ((wp = strtok (NULL, " ")))       /* repeat for each word in str      */
    {
        i = 0;
        censored = 0;

        memcpy (strchr (buffer, 0), " ", 1);
        p = strchr (buffer, 0);             /* (get address of null-term char)  */

        while (bad[i])
        {
            if (strcmp (wp, bad[i++]) == 0)
            {
                memcpy (p, rep, strlen (rep));
                censored = 1;
            }
        }

        if (!censored)
            memcpy (p, wp, strlen (wp));
    }

    if (savp) free (savp);                  /* free copy of strtok string       */
    return buffer;
}

int main ( int argc, char** argv)
{   
    unsigned int i = 0;
    char str[SMAX] = {0};
    char *badwords[WMAX] = {0};             /* array to hold command line words */

    for (i = 1; i < argc; i++)              /* save command line in array       */
        badwords[i-1] = strdup (argv[i]);

    i = 0;                                  /* print out the censored words     */
    printf ("\nCensor words:");
    while (badwords[i])
        printf (" %s", badwords[i++]);
    printf ("\n\n");

    printf ("Enter string: ");              /* promt to enter string to censor  */

    if (fgets (str, SMAX-1, stdin) == NULL)
    {
        fprintf (stderr, "error: failed to read str from stdin\n");
        return 1;
    }

    str[strlen (str) - 1] = 0;              /* strip linefeed from input str    */

    /* print out censored string */
    printf ("\ncensored str: %s\n\n", replace_str (str, badwords, "CENSORED"));

    i = 0;                                  /* free all allocated memory        */
    while (badwords[i])
        free (badwords[i++]);

    return 0;
}

使用/输出

./bin/censorw bad realbad

Censor words: bad realbad

Enter string: It is not nice to say bad or realbad words.

censored str: It is not nice to say CENSORED or CENSORED words.