parsing a character array

Posted on 2006-06-15
Last Modified: 2010-04-01
I have the following object:

const u_char* pData;

Inside this object is a bunch of junk. "adfasdfasdf11=asdfasdf"  What is the easiest way to find where the 11= begins in this object.

Question by:rspiege1
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Expert Comment

ID: 16914663
You can use strstr
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Accepted Solution

Axter earned 125 total points
ID: 16914702
#include <string.h>

const u_char* pData = "adfasdfasdf11=asdfasdf";
const char* srchStr = "11";
char *pdest = strstr( pData, srchStr);

if ( pdest != NULL )
  int result = (int)(pdest - pData + 1);
  printf( "%s found at position %d\n", srchStr, result );


Author Comment

ID: 16914923
It seems to work.  I had to add (Char*) casting for pData in two lines above to get it to compile.  The only thing is it does not return an integer.  instead i get a bunch of garbage.  It may be what I have stored in pData.
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Author Comment

ID: 16914966
Do you know if I could be loosing something then i convert things from a u_char* to a char*?
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Expert Comment

ID: 16914976
>>The only thing is it does not return an integer.

It returns a pointer to the position where the string starts.
You have to use pointer arithmitic to get the index int value, as in above example:
int result = (int)(pdest - pData + 1); //Pointer arithmetic
LVL 30

Expert Comment

ID: 16914995
>>Do you know if I could be loosing something then i convert things from a u_char* to a char*?

I don't think that's the problem.

Try posting your new code.

Author Comment

ID: 16915152
you solved what I was looking for.  thank you for the help.  My problem is that pData is being filled while using the WinPcap library and it is the way it is reading things.  I'll figure that piece out.


Author Comment

ID: 16915207
actually one more question.  is there a function in c++ to search for a string inside a string.

string temp = "hello world";

how could i search to see if world is in this string?


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