strtok and '\r\n'

Code:

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char delims = ',';
	char* result = NULL;
	result = strtok( _buffer, delims );
	vector<double> v;
		while (result != NULL) { //and !endOfLine
			result = strtok( NULL, delims );
			v.push_back( atof(result) );
		}
         InsertInVectorOfVector(v)

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Hello,
I have to read the _buffer into a a vector; problem is that I need also to check when I step over the '\r\n', because in this case I need to insert 'v' in a vector of vector; Is there a way to do that control using strtok() ?

Thanks,

You could use a copy of buffer and use strtok(_buffer, '\r') on that and compare the pointers. But if _buffer is very large, that's not really an option.

My suggestion would be to use QByteArray and its members QByteArray::indexOf() and QByteArray::left() and optionally QByteArray::simplified() to get the data from your buffer.

Quote:

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Originally Posted by lvi

You could use a copy of buffer and use strtok(_buffer, '\r') on that and compare the pointers. But if _buffer is very large, that's not really an option.
My suggestion would be to use QByteArray and its members QByteArray::indexOf() and QByteArray::left() and optionally QByteArray::simplified() to get the data from your buffer.

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I can't use qt library; only the c++ standard library

In that case...
I would first tokenize the buffer by strtok(_buffer, '\n') and then tokenize by strtok(_buffer, ','):

Code:

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char* line = strtok(_buffer, '\n');
while (line) {
    char* c = strtok(_buffer, ',');
    while (c) {
        double number = atof(c);
        c = strtok(NULL, ',');
    }
    line = strtok(NULL, '\n');
}

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Or you could use std::string::first_index_of() and std::string::substr() to achieve the same:

Code:

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int lineStart = buffer.first_index_of('\n');
int lineEnd = buffer.first_index_of('\n', lineStart + 1);
std::string line = buffer.substr(lineStart, lineEnd - lineStart);

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In some loop... str::first_index_of returns std::npos if the delimeter is not found.

Since your lines are terminated by \r\n, you need to use do something smart with the pointers/indices (e.g. increment by 1 appropriately).

Use code at own risk ;-)

Hello,
IMHO there's an error in the first version of your code ( the second strtok); this is my version of code (probably is what you wanted); anyway it doens't work because at //*, line takes "nullptr" and this first loop end...any hints?

Code:

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vector<double> v;
	vector< vector<double> > doubleVector;
	char* line;
	line = strtok(_buffer, "\r\n");
	while ( line != NULL ) {
		cout << line << endl;
		char* value = strtok(line, ",");
			while ( value != NULL) {
				cout << value << endl;
				v.push_back( strtod(value, NULL) );
				value = strtok(NULL, ",");			
			}		
		doubleVector.push_back(v);
		v.clear();
		line = strtok(NULL, "\r\n");	//*	<------ problem
	}

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You are right about the second strtok. But my code is flawed anyway ;)

My best guess would be that on line #15 the buffer has no newlines left:

Code:

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// buffer: 0,1,2,3,4\r\n5,6,7,8,9\r\n
line = strtok(buffer, "\r\n");   // buffer: 0,1,2,3,4\0\n5,6,7,8,9\r\n
value = strtok(line, ',');       // buffer: 0\01,2,3,4\0\n5,6,7,8,9\r\n
while ( value != NULL ) {
    value = strtok(NULL, ',');
}
// at this point, buffer: 0\01\02\03\04\0\n5,6,7,8,9\r\n

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You'd need to fiddle around with some pointers to get past the \0. But then again you need to be careful not to get a segfault at the end of your buffer or something.
I suggest you use std::string, it will save you tons of trouble :)

hello,
I'm trying to work with this code but it doens't work with ','; any helps, please?

Code:

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istringstream is("100,200,300", istringstream::in);
	int num;
	vector<int> vec;
	is.exceptions(~ios::goodbit);
	try {
		while ( is.good() ) {
			is >> num;
			vec.push_back(num);
			if (is.peek() == ',') 
				is.ignore(1);				
		}
	}
	catch(ios_base::failure failure) {
		assert (!is.good());
		if (!is.eof()) {
			is.clear();  
		}
	}

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It works fine only with a space between the numbers (but even in this case, at the end of scanning, an exception is thrown