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strcmp seg faulting in a loop

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strcmp seg faulting in a loop

 
0
  #1
Apr 26th, 2009
Hi,
Here's my code
C++ Syntax (Toggle Plain Text) 
  1. #include<iostream>
  2. #include<fstream>
  3. #include<string.h>
  4. #include<math.h>
  5. #include<stdlib.h>
  6. #include<stdio.h>
  7.  
  8. using namespace std;
  9.  
  10. int cIndex(char *x,char **featlist,int len)
  11. {
  12. 	int i;
  13. 	for(i=0;i<len;i++)
  14. 	if(strcmp(x,featlist[i])==0)
  15. 	return i;
  16. }	
  17.  
  18. int main(int argc,char *argv[])
  19. {
  20. 	std::ifstream featFile(argv[1],ios::in);
  21. 	std::ifstream trainFile(argv[2],ios::in);
  22. //	std::ofstream svmFile(argv[3],ios::out);
  23. 	char line[20000];
  24. 	char feat[100];
  25. 	char **featlist;
  26. 	int i=0,len=0,fl=0,j;
  27. 	char* x;
  28. 	int valnum;	
  29. 	while(featFile.good())
  30. 	{
  31. 		featFile.getline(feat,100,'\n');
  32. 		if(featFile.eof()) break;
  33. 		len++;
  34. 	}
  35. 	featFile.clear();
  36. 	featFile.seekg(0,ios::beg);
  37. //	cout<<len<<endl;
  38. 	featlist=new char*[len];
  39. 	for (i = 0; i < len; ++i)
  40.         featlist[i] = new char[100];
  41. 	i=0;
  42. 	while(featFile.good())
  43. 	{
  44. 		featFile.getline(feat,100,'\n');
  45. 		if(featFile.eof()) break;
  46. 		strcpy(featlist[i],feat);
  47. 		i++;
  48. 	}
  49. 	while(trainFile.good())
  50. 	{
  51. 		trainFile.getline(line,20000,'\n');
  52. 		x=strtok(line," ");
  53. 		valnum=cIndex(x,featlist,len);
  54. 		cout<<valnum<<";";		
  55.  
  56. 	}
  57. 	trainFile.close();	
  58.  
  59. }

my featFile is of the form
C++ Syntax (Toggle Plain Text) 
  1. yasuhiro
  2. ali
  3. mdbl
  4. consum
  5. dollar
  6. unrest
  7. protest
  8. mile
  9. mill
  10. ventur
  11. semiconductor
  12. heller
  13. authoris

and my trainFIle is of the form
C++ Syntax (Toggle Plain Text) 
  1. acq 1:0 2:0 3:0 4:0 5:0 6:0 7:0 8:0 9:0 10:0 11:0 12:0 13:0 14:0 15:0 16:0 17:0 18:0 19:0 20:0 21:0 22:0 23:0 24:0 25:0 26:0 27:0 28:0 29:0 30:0 31:0 32:0 33:0 34:0
  2. acq 1:0 2:0 3:0 4:0 5:0 6:0 7:0 8:0 9:0 10:0 11:0 12:0 13:0 14:0 15:0 16:0 17:0 18:0 19:0 20:0 21:0 22:0 23:0 24:0 25:0 26:0 27:0 28:0 29:0 30:0 31:0 32:0 33:0 34:0

so i basically have to read the training file and replace the first name with an array index...the array index is formed using the featFile...the call to cIndex keeps seg faulting after some iterations.
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Re: strcmp seg faulting in a loop

 
0
  #2
Apr 26th, 2009
> The function cIndex isn't always returning a value:
C++ Syntax (Toggle Plain Text) 
  1. int cIndex(char *x,char **featlist,int len)
  2. {
  3. 	int i;
  4. 	for(i=0;i<len;i++)
  5.             if(strcmp(x,featlist[i])==0)
  6. 	        return i;
  7.         /* So what happens when featlist[i] and x aren't equal ? */
  8.         /* You should add a return code to check whether they were equal or not */
  9.         /* Let's say if they weren't equal you return -1 for example */
  10. }

> Your code compiled and ran fine for me (what OS and compiler are you using?)

> Running your code gave me the following output: -7;-7; , is that correct? (I'm using the same file contents for featFile and trainFile as you provided)

> I can't seem to find any place in your code where you're deallocating the assigned memory to featlist , that's a serious memory leak ...
Last edited by tux4life; Apr 26th, 2009 at 6:06 am.
"Never argue with idiots, they just drag you down to their level and then beat you with experience."
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Re: strcmp seg faulting in a loop

 
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  #3
Apr 26th, 2009
To release the allocated memory (of your featlist ):
C++ Syntax (Toggle Plain Text) 
  1. for(int i = 0; i < len; i++)
  2.      delete[]  ptr[i];
So, no more memory leaks
Last edited by tux4life; Apr 26th, 2009 at 6:20 am.
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Re: strcmp seg faulting in a loop

 
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  #4
Apr 26th, 2009
ok...It was the return value! thanks a lot! memory leaf fixed
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