text: #include "sys.h"
  
  using namespace std;
  
  char* str_to_char(string str)
  {
      char* c = 0;
      int n = str.size();
  
      c = new char[n+1];
      copy(str.begin(), str.end(), c);
      c[n] = '\0';
      return c;
  }
  