[Work] command line parser and usage

void usage(const char *myname)
{
  fprintf(stderr, "Usage: %s infile [options] \n", myname);
  fprintf(stderr, "Options:\n");
  fprintf(stderr, "       -help          this page\n");
  fprintf(stderr, "       -lw            line width\n");
  fprintf(stderr, "       -cl            low threshold of curvature\n");
  fprintf(stderr, "       -cu            up  threshold of curvature\n");
  fprintf(stderr, "       -rs_iter_max   maximum iteration number of ridge searching\n");
  fprintf(stderr, "       -beta          the beta\n");
  fprintf(stderr, "       -d_max_search  the maximum distance threshold before ridge searching\n");
  exit(1);
}


void parse_cmd(int argc, char** argv){
  if(argc<2) 
    usage(argv[0]);
  for (int i = 1; i < argc; i++) {
    if (!strcmp(argv[i], "-help")){
      usage(argv[0]);
    }
    if (!strcmp(argv[i], "-lw")){
      i++;
      lw=atof(argv[i]);
    }else if(!strcmp(argv[i], "-cl")){
      i++;
      cl=atof(argv[i]);
    }else if(!strcmp(argv[i], "-cu")){
      i++;
      cu=atof(argv[i]);
    }else if(!strcmp(argv[i], "-rs_iter_max")){
      i++;
      rs_iter_max=atoi(argv[i]);
    }else if(!strcmp(argv[i], "-beta")){
      i++;
      beta=atof(argv[i]);
    }else if(!strcmp(argv[i], "-d_max_search")){
      i++;
      d_max_search=atof(argv[i]);
    }
  }
}