Notes on C++

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 );
        }
    
    
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