nsignificantdigits()

int datrw::util::nsignificantdigits	(	double	v,
		const bool &	debug
	)

return number of significant digits

Examples:

writetest.cc.

Definition at line 49 of file util.cc.

Referenced by main(), ntrailingdigits(), and datrw::su::ScalCoo::set().

    {
      const double epsilon=1.e-30;
      if (debug) 
      { 
        std::cerr << "DEBUG (nsignificantdigits): "
          << "entered function for value:" << v << std::endl; 
      }
      if (v<0) { v = -v; }
      int n=0;
      if (v<epsilon) 
      {
        n=2;
      }
      else
      {
        double basefactor=pow(10.,-floor(log10(v)));
        double v1,v2;
        if (debug) 
        { 
          std::cerr << "DEBUG (nsignificantdigits): "
            << "basefactor: " << basefactor << " "
            << "v: " << v << " "
            << std::endl; 
        }
        do
        { 
          double factor=basefactor*pow(10.,n);
          v1=v*factor;
          v2=floor(v1);
          n++;
          if (debug) 
          { 
            std::cerr << "DEBUG (nsignificantdigits): "
              << "factor: " << factor << " "
              << "n: " << n << " "
              << "v1: " << v1 << " "
              << "v2: " << v2 << " "
              << std::endl; 
          }
        }
        while (v1 != v2);
      }
      return (n);
    } // int nsignificantdigits(const double& v)

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