String to Hex

#include <iostream>
#include <sstream>
#include <iomanip>
using namespace std;
char * HexConvert(char* message,int lenght){
    ostringstream str;
    for (int i = 0; i < (lenght-1); i++){
        str << hex << setw(2) << setfill('0') << (int)((unsigned char)message[i]);
    }
    str << '\x00';
    auto ret = new char [(lenght * 2)+1];
    strncpy_s(ret,(lenght*2)+1, (char*)str.str().c_str(), (lenght * 2) + 1);
    return ret;
}
int _tmain(int argc, _TCHAR* argv[])
{
    cout << HexConvert("\xff\x00", 3)<<endl;
    system("PAUSE>NUL");
}