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  #1  
Old 11-Oct-2008, 20:01
n00pster n00pster is offline
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Performance of find(string,size_t) in string class of STL

Hello All,

Does any of you know the runtime performance of the following function in string class of STL?

size_t find ( const string& str, size_t pos = 0 ) const;

Also, it would be great if you have any information on how a string is stored (I think a map is stored as red black tree, so maybe string also is stored the same way??)

Regards,
n00pster
  #2  
Old 11-Oct-2008, 21:23
ocicat ocicat is offline
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Re: Performance of find(string,size_t) in string class of STL

Quote:
Originally Posted by n00pster
Also, it would be great if you have any information on how a string is stored (I think a map is stored as red black tree, so maybe string also is stored the same way??)
Given that string::c_str() returns a pointer to a C-style string, I doubt it is implemented as a red-black tree. Sometimes complex solutions are overkill.
  #3  
Old 11-Oct-2008, 23:14
Peter_APIIT Peter_APIIT is offline
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Re: Performance of find(string,size_t) in string class of STL

What you mean how string is stored ?
  #4  
Old 12-Oct-2008, 00:01
n00pster n00pster is offline
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Re: Performance of find(string,size_t) in string class of STL

Quote:
Originally Posted by Peter_APIIT
What you mean how string is stored ?
This is what I meant: When a string object is initialized, how does it store the characters internally? Does it use just a char array? I don't think it is stored in a char array. I guess it uses a some data structure that allows fast substring matching.

I did google it, but without luck. I thought may be somebody here might already know so that I don't have to dig more.
  #5  
Old 12-Oct-2008, 00:22
ocicat ocicat is offline
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Re: Performance of find(string,size_t) in string class of STL

Quote:
Originally Posted by n00pster
I don't think it is stored in a char array. I guess it uses a some data structure that allows fast substring matching.
Given that the std::string class has a c_str() member function, I would recommend you access the beginning address of a string. & then step through each element looking at its address. You will find that instances of std::string are simply C-style character arrays.
Quote:
I did google it, but without luck.
A number of Open Source compilers make source available. You can always study the code yourself.
  #6  
Old 12-Oct-2008, 01:04
n00pster n00pster is offline
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Re: Performance of find(string,size_t) in string class of STL

Quote:
Originally Posted by ocicat
Given that the std::string class has a c_str() member function, I would recommend you access the beginning address of a string. & then step through each element looking at its address. You will find that instances of std::string are simply C-style character arrays..

Oh no, I can't believe I didn't think of this. That was the easiest thing to do. :-) thanks a lot, I checked it and yes you are right without doubt.

Quote:
A number of Open Source compilers make source available. You can always study the code yourself.
I know, but I am out of time now.. really appreciate your fast responses..
  #7  
Old 12-Oct-2008, 19:41
Peter_APIIT Peter_APIIT is offline
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Re: Performance of find(string,size_t) in string class of STL

Quote:
A number of Open Source compilers make source available. You can always study the code yourself.

What kind of open source compiler do ofer source code ?

I using dev cpp, code blocks and others also.

Thanks.
  #8  
Old 12-Oct-2008, 19:57
ocicat ocicat is offline
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Re: Performance of find(string,size_t) in string class of STL

Quote:
Originally Posted by Peter_APIIT
What kind of open source compiler do ofer source code
GNU's GCC compiler suite.
 
 
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