c++ - Vector of comma separated token to const char** -

i trying convert comma separated string vector of const char*. following code, expected output is

abc_ def hij 

but get

hij def hij 

where going wrong?

code:

#include <iostream> #include <boost/tokenizer.hpp> #include <vector> #include <string> using namespace std;  int main() {    string s("abc_,def,hij");    typedef boost::char_separator<char> char_separator;    typedef boost::tokenizer<char_separator> tokenizer;     char_separator comma(",");    tokenizer token(s, comma);    tokenizer::iterator it;     vector<const char*> cstrings;     for(it = token.begin(); != token.end(); it++)    {       //cout << (*it).c_str() << endl;       cstrings.push_back((*it).c_str());    }     std::vector<const char*>::iterator iv;    for(iv = cstrings.begin(); iv != cstrings.end(); iv++)    {       cout << *iv << endl;    }    return 0; } 

http://ideone.com/3tvnus

edit: solution of answers below: (paulmckenzie offers neater solution using lists.)

#include <iostream> #include <boost/tokenizer.hpp> #include <vector> #include <string> using namespace std;  char* createcopy(std::string s, std::size_t buffersize) {    char* value = new char[buffersize];    memcpy(value, s.c_str(), (buffersize - 1));    value[buffersize - 1] = 0;    return value; }  int main() {    string s("abc_,def,hij");    typedef boost::char_separator<char> char_separator;    typedef boost::tokenizer<char_separator> tokenizer;     char_separator comma(",");    tokenizer token(s, comma);    tokenizer::iterator it;     vector<const char*> cstrings;     for(it = token.begin(); != token.end(); it++)    {       //cout << it->c_str() << endl;       cstrings.push_back(createcopy(it->c_str(),                                       (it->length() + 1)));    }     std::vector<const char*>::iterator iv;    for(iv = cstrings.begin(); iv != cstrings.end(); iv++)    {       cout << *iv << endl;    }     //delete allocations new    //...    return 0; } 

here's thing: boost::tokenizer::iterator doesn't return ownership of copy of string, refernce internal copy.

for example, after running code get:

hij hij hij 

the solution replace cstrings.push_back((*it).c_str()) 1 of following:

    char* c = new char[it->length() + 1];     c[it->length()] = 0;     cstrings.push_back(c);     std::strncpy(c, it->c_str(), it->length()); 

doesn't pretty, won't faster (at least if want use boost::tokenizer.

other option totally replace boost::tokenizer e.g. strtok - example can found here: c split char array different variables

you can use boost::algorithm::string::split, might need remap string const char* later on.