#ifndef arg_parser_h
#include <string>
#include <sstream>      // for formatting error msgs

class arg_parser{
public:
  int argc;
  char** argv;
  std::string cur;

  arg_parser(const int _argc, char** _argv)
  : argc(_argc), argv(_argv) {}

  std::string next(){
    cur = *argv++; argc--;
    return cur;
  }

// see if cur arg is a prefix of patt */
  int prefix(const std::string patt, const int need){
    if (cur != patt.substr(0, cur.length())) return 0;
    if (need > argc){
      ostringstream buf;
      buf << "Option " << cur;
      if (need ==1) buf << " requires an argument.";
      else buf << " requires " << need << " arguments.";
      throw buf.str();
    }

    return 1;
  }

  int prefix(const std::string patt){
    return prefix(patt, 0);
  }
};

#define arg_parser_h
#endif