can't open input file

[mms]

Hi All,
I have tried to run this program, however, the error state the file cannot open. Actually in a single file, I want to read the same text file twice. For the first time, I succeed. However an error receive when the program want to read the file the second time. I have read lots of article, try to modify the program, the result is the same. I wonder why, pls anybody, any suggestion?? thanks

#include <iostream>
#include <vector>
#include <string>
#include <cstring>
#include <cstdlib>

#include "Dataset.h"
using std::cerr;
using std::ios;
using std::ifstream;
using std::string;
using std::cout;
using std::endl;

Dataset::Dataset(void)
{

  pmtr.svm_type = C_SVC;
  pmtr.kernel_type = SIGMOID;
  pmtr.degree = 3;
  //pmtr.gamma = 0;
  pmtr.coef0 = 0;
  pmtr.nu = 0.5;
  pmtr.cache_size = 100;
  pmtr.C = 1;
  pmtr.eps =1e-3;
  pmtr.p = 0.1;
  pmtr.shrinking = 1;
  pmtr.probability = 0;
  pmtr.nr_weight = 0;
  pmtr.gamma = 0.001;
  pmtr.weight_label = NULL;
  pmtr.weight = NULL;
}

Dataset::~Dataset(void)
{
}
void Dataset::getDataset(std::ifstream &infile)
{
 position = 0;
 elements = 0;
 attributes = 0;
 problem.l = 0;
 int c = 0;
 char character;
 string s; 

 infile.open("C:\\visual C\\heart_scale.txt", ios::in); 
 
 if (!infile)
 {
	 cerr << "Cant Open the File\n";

	 exit(1);
 }

 while (infile.get(character))
 {
	 //if (character=='\n') break; 
	 if (character==':') 
	 { 
		 ++attributes;
	 } // count attributes
	  
	 
 }
 infile.seekg(0); 
 while(!infile.eof())
  {
	  infile.get(character);

	switch (character)
	{
	case '\n':
		++problem.l;
	  	
	case ':':
		elements++;
    case EOF:
		 break;
        
	default:
		;
  
	} // end of switch
 
   } // end of while
 infile.seekg(0);
 //infile.close();
 Dataset::getSvmNodeDetails(infile, c, attributes);
 model = svm_train(&problem,&pmtr); 
 makePrediction();

} // end of getDataset

void Dataset::makePrediction()
{
  int correct_classification;
  double error = 0;
  double target;
  double v;
  double *estimates = NULL;
  int svm_type = svm_get_svm_type(model);
  int nr_class = svm_get_nr_class(model);
  int *classes =(int *) malloc(nr_class*sizeof(int));

  svm_get_labels(model, classes);
  estimates=(double *) malloc(nr_class*sizeof(double));
  

  for (i = 0; i<=problem.l; i++)
  {
	  v = svm_predict(model, problem.x[i]);
	  if (problem.y[i] != v) {error++;}
  } // end of for
  std::cout << error << std::endl;

}

void Dataset::getSvmNodeDetails(std::ifstream &infile, int c, int attibutes)
{
 	
	infile.open("C:\\visual C\\heart_scale.txt",ios::in); //this is where i cannot open file 
 	

     if (!infile)
 {
	 cerr << "can't open input file\n";

	 exit(1);
 }

	problem.y = Malloc(double,problem.l);
	problem.x = Malloc(struct svm_node *, problem.l);
	x_values = Malloc(struct svm_node, elements + problem.l);

	int max_index = 0;
	j = 0;
	char character;
	char ch[2];
	char val [80];
	char attrib [3000];
    int countch = 0;
	int k;
	char *stringPtr;
	//char *endLine;

    int lenght = 0;
	// Get Label
	for(i = 0;i< problem.l; i++)
 {
   infile.get(character);
   ch[countch] = character;
   countch++;

   if (countch==2) 
   {
	   ch[countch] = '\0';
	   
	   if ((ch[0] == '+') && (ch[1] =='1'))
	   {
		   problem.y[i] = 1; 
	   }
        
		if ((ch[0] == '-') && (ch[1] =='1'))
	   {
		   problem.y[i] = -1; 
	   }

	   while(infile.get(character))
	   {
		   if (character=='\n') break;
	   } 

	   countch = 0;
   }
 }  // end of Loop

	// Goto begining of the file 
	infile.seekg(0);

	for (i=0;i<problem.l; i++)
	{
		problem.x[i] = &x_values[j];
		k = 0;
		j = 0;

	   while(infile.get(character))
	   {
		   if (character==' ') break;
	   } 

       	while(!infile.eof())
		{			
			//problem.x[i] = &x_values[j];
			infile.get(character);
			
			if (character != ':')
			{
				attrib[k] = character;
                k++;
			}

		 	if (character=='\n')
			{
				attrib[k] = '\0';
				// end of vector

	//			problem.x[i] = &x_values[j];
				x_values[j++].index = -1;
	//			problem.x[i] = &x_values[j];
     			j= 0;
				k = 0;
				break;
			}
     		if (character == ':')
			{
				j++;
				attrib[k] = '\0'; 
				k = 0;
				
				infile.getline(val,80,' ');
			//	lenght = strlen(val);
			//	endLine=strrchr(val,'\n');
				x_values[j].index = atoi(attrib);
				x_values[j].value = strtod (val,&stringPtr);
				
			
			} //

		} // end of while 
	} // end of for Loop  

	infile.close();
} // end of getSVMDetails  

[Bazzy]

So, you are calling getSvmNodeDetails (which opens the file) in getDataset:

infile.open("C:\\visual C\\heart_scale.txt", ios::in); 

some stuff ...

//infile.close();
Dataset::getSvmNodeDetails(infile, c, attributes);

When that function gets called, infile is already open so you cannot open it again. Uncomment the line you hav just before calling that function and it should work.

Please use [code][/code] tags when posting conde

[mms]

Thank u Bazzy, I have uncomment the part, but still the error is the same..

[Incubbus]

im not sure about this, but try to clear the error state, which is set when reaching eof, by calling infile.clear()...

or ur stream will be cought up with the failbit/badbit, as far as i remember^^... and u cant work with the stream again until u clear it...

[mms]

Incubbus, thanx for your reply, but im sorry, i'm not sure, which error state I should clear??

[Incubbus]

a stream has an error state... normally (without errors) its "good"... you can check this via infile.good()...

as we can see in your code u do perfom file transactions until you reach eof() = true...

when reaching EOF the stream object´s error state ist set and needs to be cleared to perfom new actions on it...

this can be done by using streamobject.clear()


compare: http://cplusplus.com/doc/tutorial/files/
http://msdn.microsoft.com/en-us/library/59zy697d.aspx


edit: please put ur codeinto the code-brackes... mark all your code and then press the '#' at the right side under "Format"-> makes it more readable...

[mms]

yes, thanks incubbus! I have solved it:)