//	FileIO_d.cc

//	Switch between Standard-IO (terminal) and 
//		Input from a file
//		Output  to a file 
// 	via command line argument : version2

// 	command line:
//	a.out -fo -fi

#include <stdlib.h>		// needed for exit
#include <iostream.h>
#include <fstream.h>		// needed for ifstream and ofstream
#include <strings.h>		// needed for exit

void CheckOptions(const int argc, const char* argv[], bool& bin, bool& bout);
void GetIOStreams(const int argc, const char* argv[], 
			istream* & myin, ostream* & myout);

int main(const int argc, const char* argv[])
{
 int  n;
//			variables for IO streams
 istream  *myin  = 0;
 ostream  *myout = 0; 

//	Decide whether terminal-IO or file-IO should be used
 GetIOStreams(argc, argv, myin, myout);
 
 (*myout) << "Input: ";
 (*myin)  >> n;
//			check
 (*myout) << endl;
 (*myout) << "Input was " << n << endl;
 (*myout) << endl;
 (*myout) << "This is an additional output" << endl;
 
 return 0;
}

// ----------------------------------------------------------------
void CheckOptions(const int argc, const char* argv[], bool& bin, bool& bout)
{
 const char FIN[]  = "-fin",
            FOUT[] = "-fout";
 bool bb[3];
 int  i;
  
 if (argc>=4) 
  {
   cout << "Wrong number of arguments in " << argv[0] << endl << endl;
   cout << "command:  " << argv[0] 
   	<< " [" << FIN << "] [" << FOUT << " ]" << endl;
   exit(-10);				// Abort programm
  }
  
 bin = bout = false;
 for (i = 1; i <= argc-1; i++)
  {
    bin  = bin  || strcmp(argv[i],FIN)==0;
    bout = bout || strcmp(argv[i],FOUT)==0;
    bb[i] = strcmp(argv[i],FIN)==0 || strcmp(argv[i],FOUT)==0; 
    if (! bb[i])
     {
      cout << " Option  " << argv[i] << "  is not valid" << endl;
      cout << " Use Options  " << FIN << "  or/and  " << FOUT << endl;
      exit(-i);
     }
  }
 
 return;
}

// ----------------------------------------------------------------
void GetIOStreams(const int argc, const char* argv[], 
			istream* & myin, ostream* & myout)
{
 const char  infilename[] = "in.txt",
            outfilename[] = "out.txt";
 bool bin, bout;

 CheckOptions(argc, argv, bin, bout);

//			input file
 istream* infile  = new ifstream(infilename);

 if (bin)
  {   
   if ( infile->bad())	// Does input file exist ?
   {
     cout << "File "<< infilename 
   	  << " nicht vorhanden" << endl;
     exit(-1);
   }
  }
//			output file
 ostream* outfile = new ofstream(outfilename); 

 if (bin) 
   {			// Remaining Input via file
     myin  = infile;
   }
 else
   {			// Remaining Input via terminal
     myin  = &cin;
   }

 if (bout) 
   {			// Remaining Output via file
     myout = outfile;
   }
 else
   {			// Remaining Output via terminal
     myout = &cout;
   } 

 return;
}