String Parsing using known delimiters? [C++]

[Shaitan00]

The age old issue of string parsing comes up again ...

I have a text file that contains lines that are SUPPOSED to follow a set format, specifically:

string, string, long string int string double int

 

The delimiters are therefore:

Comma (,) for the first two fields

Spaces for all other fields

 

Strings like this would be valid:

Jon, Jack, 100 CPN 5 KTE 1.00 10

Jon, Jack 100 CPN 5 KTE 1.00 10 // notice the extra spaces

 

Whereas something like these would be considered invalid:

Jon Jack 100 CPN 5 KTE 1.00 10 // missing the commas

Jon, Jack, 100 CPN 5 KTE 1.00 // missing the last field "10"

Jon, Jack, 100CPN 5 KTE 1.00 10 // missing space between "100" and "CPN"

 

The goal is to EXTRACT each section and store them, and if possible determine when a string is INVALID (does not follow format).

I have a class with the following data members:

class A

{

private:

	// Record

	string A

	string B

	long C;

	string D;

	string E;

	string F;

	double G;

	int H;



public:

	A(string sLine);	// constructor

};



A::A(string sLine)

{

	// somehow parse the string here and determine if it is valid //

}

[/Code]

 

 

So, how can I parse the string (sLine) and extract each piece into there components (A, B, C, D, E, F, G, H)...

I was thinking of using the old method of simply doing substring searches but I find it very error prone and long ... is there a better way to accomplish this?

 

Anything anyone would recommend?

Any help would be much appreciated...

Thanks,

[snarfblam]

In this sort of case I tend to scan the string char by char seeking for delimiters, extracting substrings. In the event of anything unexpected (extra delimiters, invalid number format, early string termination), I would consider the input invalid.

 

Regular expressions might also be an option.

[Shaitan00]

marble_eater: RegEx would rock ... but I can't use BOOST or any 3rd party applications - it must be something included with VS 2008 ... Does VS 2008 have a built in REGEX?

[snarfblam]

As far as I know, this would only be the case if your app is managed (DotNet).

[Shaitan00]

Well - I am using C++ VS2008 - I assume this is automatically DotNet no?

But I try to #include <regex> and it doesn't find it ...

 

any clues?

[snarfblam]

Just because you are using VS 2008 deosn't mean that the app is DotNet. If you are writing a "C++/CLI" app, then it will be DotNet. If you aren't sure, a simple way to check is see if you can access anything in the System namespace. I don't have much experience with C++/CLI, but from what I gather, libraries are included via a using statement, rather than an include.

#include <iostream>
#using <mscorlib.dll>
#using <System.Text.dll>

// ...

System::Text::RegularExpressions::Regex ^x = 
   gcnew System::Text::RegularExpressions::Regex("pattern"):

The above should compile only if your app is managed (I haven't tested it either way).

[Shaitan00]

Humm - guess it isn't a DotNet application then ...

When I tested your code I get the following error:

Error 1 fatal error C1190: managed targeted code requires a '/clr' option