Extract data from LIBSVM format

gistfile1.c

/* strtok example */
#include <stdio.h>
#include <cstring>
#include <string>
#include <vector>
using namespace std;
int main ()
{
  char str[] ="1 1:1 2:2 3:3";
  char * pch;
  vector<string> res;
  pch = strtok (str," ");
  while (pch != NULL)
  {
    printf ("%s\n",pch);
    res.push_back(pch);
    pch = strtok(NULL, " ");
  }
  for(int i=0;i < res.size();i++)
  {
      if(i == 0)
      {
          printf("label\n");
      }
      else
      {
          char *tem = new char[5];
          char * subpch;
          strcpy(tem, res[i].data());
          subpch = strtok(tem, ":");
          while(subpch !=NULL)
          {
              printf("%s\n", subpch);
              subpch = strtok(NULL, ":");
          }
      }

  }
  return 0;
}