hello everyone i use

while(getline(cin,s)){
    if(s == "\0") break;

for end of file but is not correct :(((

It's hard to tell what's wrong without looking at your code.

You can take a look at my code.

#include <string>
#include <map>
#include <iostream>
#include <ctype.h>
#include <sstream>
using namespace std;
stringstream in;
void c(string& s) {
    string p=",.;'\"()/:-";
    for (int i=0;i<s.length();i++) {
        if (p.find(s[i]) == string::npos) in << (char)tolower(s[i]);
        else  in << " ";
    }
    in << " ";
}
int main () {
    map<string,int> m;
    string s;
    int mx = 0;
    while (cin >> s) c(s);
    while (in >> s) {
        if (m.find(s) == m.end()) m[s]=0;
        m[s]++;
        mx = max(mx, m[s]);
    }
    cout << mx << " occurrences" << endl;
    for (map<string,int>::iterator it=m.begin();it!=m.end();it++) if (it->second == mx) cout << it->first << endl;
    return 0;
}

#include <iostream>
#include <map>
#include <iomanip>
#include <sstream>
using namespace std;
template <typename T> string to_str(T& c){
ostringstream s;
s << c;
return s.str();
}
string ff(string f){
string r;
for(int i=0;i<f.length();i++){
    char c =  tolower(*(f.substr(i,1).c_str()));
    if (c == ',' || c == '.' || c == ':' || c == ';'
        || c == '"'|| c == '\'' || c == '('|| c == ')'
        || c == '"'|| c == '\\' || c == '/'|| c == '-')
    {

    }
    else
        r.append(to_str(c));
}
return r;
}
int main()
{
    string s;
map<string, int> m;
int mx=0;
while(getline(cin,s)){
    if(s == "\0") break;
    while(s.length()>0){
        int i;
        string f;
        if((i=s.find(" "))>=0){
            f = ff(s.substr(0,i));
            s = s.substr(i+1);
        }else
        {
            f = ff(s);
            s.clear();
        }
        map<string, int>::iterator it = m.find(f);
        if(it != m.end()){
            m[f] += 1;
            if (mx < m[f])
                mx = m[f];
        }
        else{
            m[f] = 1;
            if (mx==0) mx=1;
        }

    }
}

cout << mx << " occurrences" << endl;
for (std::map<string,int>::iterator it=m.begin(); it!=m.end(); ++it)
    if(it->second == mx)
        cout << it->first << endl;

return 0;
}