Word counts in files

FileChecker.cpp

#include <iostream>
#include <fstream>
#include <map>

using namespace std;


class FileChecker {
private:
    map<string, unsigned> keywords;

public:
    FileChecker(const string &keyword_filename)
    {
        ifstream kwfile(keyword_filename.c_str());

        string tmp;
        while (kwfile >> tmp) {
            keywords[tmp] = 0;
        }
        kwfile.close();
    }
    void check(const string &filename)
    {
        for (map<string, unsigned>::iterator it = keywords.begin(); it != keywords.end(); ++it) {
            it->second = 0;
        }

        ifstream file(filename.c_str());

        string tmp;
        while (file >> tmp) {
            if (keywords.find(tmp) != keywords.end()) {
                keywords[tmp]++;
            }
        }

        file.close();

        cout << filename << ":" << endl;
        for (map<string, unsigned>::iterator it = keywords.begin(); it != keywords.end(); ++it) {
            cout << "    " << it->first << ": " << it->second << endl;
        }
        cout << endl;
    }
};

int main()
{
    FileChecker fc("keywords.txt");
    fc.check("ling/3-1msg1.txt");
    fc.check("ling/3-1msg1.txt");
}