Help with Maps... Couple Errors

I got this assignment for my class. Its to create and write an interactive program to scan and process an input stream of an ordinary text. Then it checks for punctuation marks, and deletes them from the word. I have all of it written but I'm getting a couple errors and I don't know why it wont work.

Code:

---

using namespace std;


typedef map<string, int> mapType;

void get_words(map<string, int>&);
void print_words(const map<string, int>&);
void clean_entry(const string&, string&);

/****************************************************************

  FUNCTION:  Main

  ARGUMENTS:  None

  RETURNS:    None           

  NOTES:      Calls the subroutine get_words and then get_words
              calls clean_entry
****************************************************************/

int main()
  {
  map<string, int> wordList;
  get_words(wordList);
  print_words(wordList);

  return 0;
  }

/****************************************************************

  FUNCTION:  Void get_words

  ARGUMENTS:  map string, integer &

  RETURNS:    None           

  NOTES:      Routine gets a word from the input stream and then
              cleans its punctuation marks.
****************************************************************/

void get_words(map<string, int>& wordList)
{
    string originalWord, cleanedWord;

    while (cin >> originalWord)
    {
      clean_entry(originalWord, cleanedWord);
     
      if (cleanedWord.length() > 0)
          wordList[cleanedWord]++;

      cleanedWord = "";
    }

}


/****************************************************************

  FUNCTION:  Void clean_entry

  ARGUMENTS:  const map string&, string&

  RETURNS:    nothing           

  NOTES:      Cleans a word from its punctuation marks. The
              first argument is the original word from input
              stream and the second contains the same word
              after cleaning.
****************************************************************/

void clean_entry(const string& source, string& target)
{
        int p1 = 0, p2;

        while(!isalnum(source[p1]) && p1 < source.length()) p1++;
        p2 = p1;

        while(isalnum(source[p2])&& p2 < source.length()) p2++;
        if( p2 == p1 ) target = "";

        else target = source.substr(p1, p2-p1);
        return;
}

/****************************************************************

  FUNCTION:  Void print_words

  ARGUMENTS:  const map string int &

  RETURNS:    None           

  NOTES:      Prints the final list of words and their frequencies
              It also prints hte number of nonempty words
              and the number of distinct words in the input stream
****************************************************************/

void print_words(const map<string, int>& wordList, int nemptyw)
{
        int i = 0;
        cout << "Nonemmpty words : " << nemptyw << endl;
        cout << "Distinct  words : " << wordList.size() << endl;

    for(mapType::const_iterator it = wordList.begin(); it != wordList.end(); ++it)
    {
                cout << setw (15);
                cout << setiosflags (ios_base::left);
                cout << it->first << " - " << it->second << "  ";
                if (++i >= 3 )
                {
                        i = 0;
                        cout << endl;
                }
    }
        cout << endl;
}

---

The Errors:

In function ‘void clean_entry(const std::string&, std::string&)’:
prog3.cc:105: warning: comparison between signed and unsigned integer expressions
prog3.cc:108: warning: comparison between signed and unsigned integer expressions


not sure what that is. When i nano prog3.out it shows...

-bash: prog3.exe: command not found

Anyone can help me out?

Quote:

---

Originally Posted by youngyou4

In function ‘void clean_entry(const std::string&, std::string&)’:
prog3.cc:105: warning: comparison between signed and unsigned integer expressions
prog3.cc:108: warning: comparison between signed and unsigned integer expressions

---

Those are warnings, not errors. You should fix them though; signed/unsigned mismatches can lead to subtle bugs in some situations (for instance, if a loop counter is counting down and the termination condition is "i >= 0", a problem could arise if i is unsigned). The basic issue is that p1 and p2 are signed ints, but source.length() returns an unsigned int. Simply casting it to int will remove the warnings.

Quote:

---

-bash: prog3.exe: command not found

---

That means either you're in the wrong directory, or the program didn't build properly. If you didn't get any errors (only warnings), then the former is more likely.

Are those lines within clean_entry?

source.length() returns a size_t. It's unsigned, p1 & p2 are not.

http://cplusplus.com/reference/string/string/length/

in clean_entry

I changed int p1 = 0, p2;
to unsigned int p1 = 0, p2;

And it got rid of the warnings...
But when i open up prog3.out for the output of my file. It still shows
-bash: prog3.exe: command not found

I would recommend changing from int to size_t instead of casting.

Hmm... I got rid of all the errors and warnings and such. I figured out why its saying that command is not found. I forgot to link and create executable file. But now when i try and create the executable file i get this..


prog3.cc:53: undefined reference to `print_words(std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, int, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, int> > > const&)'

Not sure what that means and it won't create it. hmm

That one occurs if you declare but don't implement a function you're trying to call. In practice, if you think you did implement it (and I certainly do see a print_words implementation there), then one of two things is usually going on:
1) There's an inconsistency between the definition and declaration, or
2) The linkage of the definition is different than the default (for instance, if you were trying to link in a function compiled as C to a C++ program without specifying "extern "C"").

In this case, the culprit is the first one. See the declaration:
void print_words(const map<string, int>&);
versus your definition:
void print_words(const map<string, int>& wordList, int nemptyw)
{
...
}