split pipe input

#include <string>
#include <vector>
#include <sstream>
#include <iostream>
using VS = std::vector<std::string>;
using VVS = std::vector<VS>;
using VChars = std::vector<const char*>;
using VVChars= std::vector<VChars>;
VS split(const std::string &s, const char delimiter)
{
    std::stringstream ss(s);
    std::string segment;
    VS lst;
    while(std::getline(ss, segment, delimiter))
        if (segment.size())
           lst.push_back(segment);
    return lst;

}
int main(int argc, char *argv[])
{
  std::string inp;
  std::getline(std::cin, inp);
  VS segPipes = split(inp, '|');
  VVS vCmds;
  VVChars vCommands;
  for (unsigned i = 0; i < segPipes.size(); ++i)
  {   vCmds.push_back(split(segPipes[i], ' '));  }

  for (unsigned i = 0; i <vCmds.size(); ++i)
  {
     VChars v;
     for (unsigned k = 0; k < vCmds[i].size(); ++k)
     {
         v.push_back(vCmds[i][k].c_str());
     }
         v.push_back((char*)NULL);
     vCommands.push_back(v);
  }

  for (auto & v:vCommands)
  {
     for(auto &s:v) if (s) std::cout << s<< " ";
        else std::cout << "NULL ";

     std::cout <<"|" <<  std::endl;
  }
  return 0;
}