Notes on C++

Last updated July 07, 2005

Last Updated: July 7, 2005.

My notes here are very sketchy since I started the web stuff after I finished with most of my C++.

1. To unmangle names c++filt // in the same dir as CC
2. Example of reading data with streams:

   #include <unistd.h>
   #include <iostream.h>
   #include <fstream.h>
   #include <stdlib.h>
   
   int main (int argc, char **argv)
   {
     cerr.precision(1);
     cerr.setf(ios::showpoint | ios::right |ios::fixed);
     int first_time=1;
     
     if(argc !=2)
       {
         cerr << "usage " << argv[0] << ": <sm4 filename>" << endl;
         exit(1);
       }
     ifstream myInputFile(argv[1], ios::in );
     if (!myInputFile)
       {
         cerr << "file " << argv[1] << " cannot be opened for reading." << endl;
         return(2);
       }
     else
       cerr << "file " << argv[1] << " opened for reading." << endl;
     
     // start reading
     double x,y,z,a;
     double xmin,xmax,ymin,ymax,zmin,zmax,amin,amax;
     
     int line_count=0;
     while ( ! myInputFile.eof() )
       {
         myInputFile >> x; myInputFile >> y; myInputFile >> z; myInputFile >> a; 
         line_count++;
         if(!(line_count % 50000))
   	cerr << ".";
         if(first_time)
   	{
   	  xmin = xmax = x;
   	  ymin = ymax = y;
   	  zmin = zmax = z;
   	  amin = amax = a;
   	  first_time =0;
   	}
         else
   	{
   	  if (x > xmax) xmax = x;
   	  if (x < xmin) xmin = x;
   	  if (y > ymax) ymax = y;
   	  if (y < ymin) ymin = y;
   	  if (z > zmax) zmax = z;
   	  if (z < zmin) zmin = z;
   	  if (a > amax) amax = a;
   	  if (a < amin) amin = a;
   	}
       }
     cerr << endl;
     cerr << "Min x, " <<  xmin << " Max X, " << xmax << endl;
     cerr << "Min y, " << ymin << " Max Y, " << ymax << endl;
     cerr << "Min z, " << zmin << " Max Z, " << zmax << endl;
     cerr << "Min attribute, " << amin << " Max Attribue, " << amax << endl;
     cerr << "number of lines " << line_count << endl;
   
     return(0);
   }
   
   

   ---

3. A routine to open an output stream:

   
   bool GridObject::writeSM4(char *filename)
   {
   
     ofstream outFile(filename, ios::out );
     if (!outFile)
       {
         cerr << "file " << filename << " cannot be opened for writing." << endl;
         return(false);
       }
     else
       {
         cerr << "file " << filename << "  opened for writing." << endl;
   	      outFile.unsetf(ios::left);
   	      outFile.width(12);
   	      outFile.precision(1);
   	      outFile.setf(ios::showpoint | ios::right |ios::fixed);
         //      outFile.setf ( ios::internal | ios::showpoint | ios::right | ios::fixed );
       }