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String Parsing using known delimiters? [C++]

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Join Date: Jul 2006

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Shaitan00

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String Parsing using known delimiters? [C++]

Jul 8th, 2009

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:

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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 //
}
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 //
}

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,

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monkey_king monkey_king is offline

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Re: String Parsing using known delimiters? [C++]

Jul 8th, 2009

What would your rule be for definingen when a token/line is invalid?
I would check the the number of tokens in each class is first 2, then 8

Or do you want a more elaborate check?

Last edited by monkey_king; Jul 8th, 2009 at 2:56 am.