simple string, search in input

Hello everybody,

I have made an activeworlds bot which have to react on chat strings.
It has to filter badwords out. The activeworlds software prevents to do that realtime, but reacting on badwords that are said is possible.

If I use this if statement:

Code:

---

if (aw_string(AW_CHAT_MESSAGE)=="badword")

---

The problem is this only works when someone 'only' says "badword" and not when saying "hello badword".

I got a suggestion from a friend:

Code:

---

char* msg = aw_string

(AW_CHAT_MESSAGE);
if (strcmp ("badword", msg) == 0) {

---

But here also the bot only reacts when I say "badword" and not when saying "hello badword".


I must admit i'm not very good in C++, more like just beginning. I've worked myself trough some examples and the tutorials and faq on this website, but couldn't find an answer for this.
If any one knows a place where this is explained then I would love to hear!

strstr() finds a string in a string.

Unless we are really bound by char*'s here, I would recommend std::string for C++ programming. And if we made this conversion, we could use the find to search for badword substrings. But with these kind of things if I said...um...like, "bass" it would target that. So what you could do is tokenize the string using the stringstream technqiue described in our very own FAQ entry on the subject

There are always tradeoffs in doing such a search. Looking for substrings that you want to indentify within the original string is the basic principle (achacha gives one example of how this can be done), but what if the "badword" is embedded in another word. Would you want to identify "assiduous" if the first three letters met screening criteria? Still, parsing strings for substrings is a time honored and often used algorhithm with many alternative strategies based on individual needs, so continue on your journey; just beware you may find potholes along the way.

Thanks for your answers!

I now use this piece of code:

Code:

---

  char* msg = aw_string

  (AW_CHAT_MESSAGE);
  if (!strstr (msg,"badword") == 0) {

  sprintf (message, "you shouldn't say that", aw_string (AW_AVATAR_NAME), (WORLD));

---

Which works perfectly, it reacts on "badword", "hi badword" ánd "hibadword". Just what I need :)


But now another question comes up. Some people will report words that they normaly use which will conflict with my "badword" search. So it should be possible to also exclude words out. Can this be done by after this check, checking for words that are ok and then skip the warning?


Now I'm thinking about this... maybe working with lists of words is more efficient, like in a badwords (and goodwords) lists, just in a .txt file.
I've looked at the ifstream tutorial on the website, that doesn't seem very difficult :) I could read and write to files.

But how do I get to check if the message (said in the chat) contains any word from that file? I know a bit of the array command from php, can I put the words in the file in some kind of array and then check the chat message for that array?

id use a string and find with a vector holding all possiblies to
search for, and have the vertor filled by a file contain the words
to be edited out. but making a file to contain all possible words
will take more effort then right this code.
if your interested in this but dont have an idea on what the code
woudl look like, i can/will provide you with a sample.

using c++ strings and find

Code:

---

if(message.find(badword, 0) != string::npos)
{
    //stuff to do here
}

---

That will find in a word. If you didn't want to find in a word, only if the word's by itself, could try just adding on a space to the start and end and searching for that

Code:

---

badword = " "+badword+" ";
if(msg.find...

---

checking for exceptions can also be done

Code:

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if(msg.find(badword, 0) != string::npos && msg.find(exception) == string::npos)

---

I'll show you an example using a file of bad words later on today maybe if I get time and noone else has, but it's easy enough to do.

Ok, from a file, it's easy enough. You'd just have your file of bad words, in a lovely little list separated by new lines or spaces, then just read them into an array.

Code:

---

ifstream in_file;
in_file.open("badwords.txt");
string bad_words[500];
int ncnt = 0;
while(in_file.good())
{
    in_file >> bad_words[ncnt];
    ncnt++;
}

---

Simple :). Then from there you can just check against them in a loop.

Thanks Dweia! This works ok now.
Only I haven't got much of an idea about how to check this in a loop. The tutorials don't provide me the information I'm looking for (or I'm not looking in a good way). Can someone help me further with any example of how to check the said chat message on the array of badwords?

Code:

---

while(whatever)
{
    if(msg.find(bad_words[ncnt], 0) != string::npos)
    {
        //your stuff here
    }
    ncnt++;
}

---

Other examples:

Goal: search a vector of strings to see if current string is in vector of strings and if so do something, otherwise do nothing.

Code:

---

//USING C++ with STL stuff
std::vector<string> badwords;
//fill badwords with individual words that will trigger an action here
std::ifstream fin("myFile.txt");
std::string temp;
std::vector<string>::iterator start = badwords.begin();
std::vector<string>::iterator stop = badwords.end();
while(fin >> temp)
{
    for( ; start != stop; ++start)
    {
      if(temp == *start)
          cout << "Naughty, naughty." << std::endl;
  }
}

---

Code:

---

//USING C++ without STL
char badwords[100][20];
//fill badwords with desired vocabulary here
ifstream fin("myFile.txt");
char temp[20];
int i = 0;
while(fin >> temp)
{
  for(i = 0; i < 100; ++i)
  {
    if(strncmp(temp, badwords[i]) == 0)
        cout << "Naughty, naughty" << endl;
  }
}

---

Quote:

---

Originally Posted by lode

Thanks for your answers!

I now use this piece of code:

Code:

---

  char* msg = aw_string

  (AW_CHAT_MESSAGE);
  if (!strstr (msg,"badword") == 0) {

  sprintf (message, "you shouldn't say that", aw_string (AW_AVATAR_NAME), (WORLD));

---

Which works perfectly, it reacts on "badword", "hi badword" ánd "hibadword". Just what I need :)

---

Does it filter "Badword"
What about "baDword"?
What if they write "baDw0rd"?
What about "B A D W O R D"?

And there are things like fvck and f\/ck. And f\_/ck.

I recommend at least converting characters to lowercase before comparing them. This should at least stop the idiots who curse because it's thrilling or something, without disrupting the "geniunely profane."

Quote:

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Originally Posted by elad

Other examples:
...

---

I tried many different ways of making this while, but didn't manage to get it working, accept for this last one you provided. I now got this part:

Code:

---

char badwords[20][20];
ifstream file_bwchk ("badwords.txt");
char temp[20];
strcpy (temp, chattext);
int i = 0;
cout << temp << endl;
while(file_bwchk >> temp) {
 for(i = 0; i < 20; ++i) {
  if(strncmp(temp, badwords[i]) == 0) {
    cout << "Naughty, naughty" << endl;
  }
 }
}

---

This one gives me this error:
/usr/include/string.h:100: error: too few arguments to function `int
strncmp(const char*, const char*, unsigned int)'
Just adding an int there won't help.. I guess I have to use that last int somewhere, but I can't exactly figure out where. When not using that int anymore than in the required line the console returns "Naughty, naughty" all the time, also when saying "test" or something like that.
Do you know how I have to use that extra int?

Quote:

---

Originally Posted by Rashakil Fol

I recommend at least converting characters to lowercase before comparing them. This should at least stop the idiots who curse because it's thrilling or something, without disrupting the "geniunely profane."

---

You're correct.. I didn't checked that :(
I searched on this site, other c++ sites, google and more, but provided examples didn't get me further than making text like "TEST" translating to "tEST" or "tEsT"...

This is where I make the variable:

Code:

---

char chattext[256];
char chatname[256];
strcpy (chattext, aw_string (AW_CHAT_MESSAGE));
strcpy (chatname, aw_string (AW_AVATAR_NAME));

---

And with these two methods (the only two I got working without errors):
["tEST"]

Code:

---

if (strcmp (chattext,"TEST") == 0) {

printf ("Before conversion: %s\n", chattext);
*chattext = tolower(*chattext);
printf ("After conversion: %s\n", chattext);
}

---

"tEsT"

Code:

---

if (strcmp (chattext,"TEST") == 0) {
printf ("Before conversion: %s\n", chattext);
for (char *iter = chattext; *iter != '\0'; ++iter) {
    *iter = tolower(*iter);
    ++iter;
}
printf ("After conversion: %s\n", chattext);
}

---

But they but don't fulle lowercase the whole word.. Is there something wrong with the translation process, or do I use the wrong type of variable?

Quote:

---

Originally Posted by lode

Code:

---

for (char *iter = chattext; *iter != '\0'; ++iter) {
    *iter = tolower(*iter);
    ++iter;
}

---

---

You're incrementing iter twice each time through the loop. This should only happen once.

Quote:

---

Originally Posted by Rashakil Fol

You're incrementing iter twice each time through the loop. This should only happen once.

---

Ah thanks! I was a bit confused by the *iter != '\0'; part (i didn't know what '\0' meant) so I didn't read the rest quite well :$

\0 is a null character, that's so that it stops trying to convert the string to lower case once it reaches the end of the string.

Quote:

---

Originally Posted by Dweia

\0 is a null character, that's so that it stops trying to convert the string to lower case once it reaches the end of the string.

---

thanks dweia!



Is there anyone who help can me further with this problem?
The while for checking for badwords, I now got this part:

Code:

---

char badwords[20][20];
ifstream file_bwchk ("badwords.txt");
char temp[20];
strcpy (temp, chattext);
int i = 0;
cout << temp << endl;
while(file_bwchk >> temp) {
 for(i = 0; i < 20; ++i) {
  if(strncmp(temp, badwords[i]) == 0) {
    cout << "Naughty, naughty" << endl;
  }
 }
}

---

This one gives me this error:

Code:

---

/usr/include/string.h:100: error: too few arguments to function `int
  strncmp(const char*, const char*, unsigned int)'

---

I guess I have to use that "unsigned int" somewhere, but I can't exactly figure out where.
When just putting an int into there without actully doing something with it the console returns "Naughty, naughty" all the time, also when saying "test" or something like that. And it does say it twenty times to, not one time :(
It looks like it is reconizing every line of the badwords.txt (which excists of 3 lines or so, not twenty) with the chattext.

Does anyone know how I have to use that extra int?

the third parameter to strncmp is the number of characters you want to compare.

As discussed earlier strncmp will only match on complete word matches, so you will not find badwords in phrases.
strstr() is better, but you're probably going to have to write your own comparision routine.

As far as the logic of your latest code...

You can either read all the badwords into an array, and then check the chattext against that array.
(harder because you'll have to dynamically adjust the array size, or at least make the array sufficiently large, and keep a count of how many words you read in)

or you can loop through the file each time and check each line against chattext
(bad if doing over and over again as file i/o is slow)

You currently have a mix of the two methods... with other problems like storing chattext in temp, and then overwriting temp with a line from badwords.txt


Here's an example of looping through the file and comparing each line to chattext
It's based off your latest code

Code:

---

        ifstream file_bwchk ("badwords.txt");
        char badword[20];

        while(file_bwchk >> badword) {
                if(strncmp(chattext, badword, strlen(badword)) == 0) {
                    cout << "Naughty, naughty" << endl;
                    break; //found a match no need to keep checking
                }
        }

---

an example of storing the words in an array first (these are just to give you an idea... much error checking needed)

Code:

---

    ifstream file_bwchk ("badwords.txt");
    char badword[20];
    char badwords[20][20];
    int badword_cnt = 0;

    while(file_bwchk >> badword) {
        strcpy(badwords[badword_cnt++], badword);
    }

    for(int i=0; i<badword_cnt; i++) {
        if(strncmp(chattext, badwords[i], strlen(badwords[i])) == 0) {
            cout << "Naughty, naughty" << endl;
            break;
        }
    }

---