while (p!=NULL)
{
    if(p=="//")
    {
    	break;
    }
    else
    {
	vec.push_back(p);
    	p=strtok(NULL," ");
    }
}

// strings and c-strings
#include <iostream>
#include <cstring>
#include <string>
#include <vector>
 
using namespace std;
 
vector<string> SplitString (string aString)
{
  vector<string> vec;
  char * cstr, *p;
 
  //string str ("Please split this phrase into tokens");
 
  string str = aString;
 
  cstr = new char [str.size()+1];
  strcpy (cstr, str.c_str());
 
  // cstr now contains a c-string copy of str
 
  p=strtok (cstr," ");
  while (p!=NULL)
  {
    // i presume a check must be done here
    vec.push_back(p);
    p=strtok(NULL," ");
  }
 
  delete[] cstr;
 
  return vec;
}
 
int main ()
{
  std::vector<std::string> vec = SplitString("Please split this phrase into tokens // this bit needs to be ignored");
 
  for (std::vector<std::string>::size_type a = 0; a < vec.size(); ++a)
  {
      cout << vec.at(a) << '\n'; 
  }	  
  return 0;
 
}

while (p!=NULL && p!="//")

while (p!=NULL)
{
unsigned int pos = str.find("//", 0);
if(pos != string::npos)
	break;
else
	vec.push_back(p);
	p=strtok(NULL," ");
}